JoeViking245

If you used the MAME Arcade Fullset Import Wizard, there's an option to create a playlist for vertically oriented games.  If you didn't un-check that option, there'll be a playlist called Vertically Oriented Games.
If you had un-selected that option, you could re-run the Wizard.  However, if have you have curated your collection in LaunchBox, that's probably not a good option.
 
Alternately...
..and follow the steps outlined in this post.
Arrange game by Screen type? - Features - LaunchBox Community Forums
 

They look great when looking through standalone MAME and adds a little pizazz to it. 
 
Yes.  Within the Extras, the image files (at least) are all named after the ROMs filename.  So when placed into the appropriate folder, LaunchBox will associate them with their respective game(s).  The DATs and ini ("folders") files can't be used in LaunchBox without the use of third-party plugins.
The Multimedia pack does have soundtracks and videosnaps that would work the same when placed in the appropriate folder.  I'm not sure about their quality. (Not saying they might be bad. I just have no idea)
 
"Can I gain anything using those over what LaunchBox has available for Arcade Images?"
Not really.  When you download MAMEs Extras, you get everything.  Say you go to pull out just the cabinet images and place them in 'their' folder, you're putting in every single image [they have].  Whereas, when you download media from LaunchBox, you get only the images for the games you actually have.
If you have an EmuMovies account (highly recommended), the same thing goes for soundtracks and videos (get only the ones you need).
 
Images available on the LaunchBox Database (where they're downloaded from) are relatively complete for Arcade machines.  As are the videosnaps from EmuMovies.  Anything that is or may be missing, chances are, they're missing from Extras and Multimedia as well.

Follow this and just change Arcade to your NES platform.
 

LaunchBox doesn't have (and pretty sure never had) an innate YouTube scraper.  There is an older user submitted "YouTube Scraper" plugin that you would have had to manually download and install yourself.   Here's a link to the Support Page for that scraper.  But it appears to have been abandoned.  To remove it, just delete the folder/file you added to the /Plugins/ folder [while LaunchBox is not running].  
There is another user submitted YT scraper plugin call Vidsnap Scraper that is currently active.  If you're looking for one.

If you're talking about seeing them in the Main (middle) section...

Go to Tools < Options < Media < Box Front Priorities, check the box for Arcade Cabinets and then click Move Selection Up until it's at the top of the list. Click OK to save and close the Options window.
Click Image Group and select Boxes.
Moving it the top selection works nice because it won't interfere with other Platforms (as they typically won't have any Arcade Cabinet images).
 
If you're talking about wanting to see them somewhere else, please elaborate.
 

Since you have your ROMs and CHDs located in the /roms/ folder under your MAME installation:
In LaunchBox, Edit your MAME emulator.  In the Default Command-line Parameters does it have -rompath %romlocation%?  If so, remove it.

Not sure if this falls under a double entendre or an oxymoron.   
Merged          - (0.273) 76.54 GB
Non-Merged - (0.273) 141.6 GB
That is course is for the Full set(s) and you'd only be exporting some of those.  So "to save space.."?  In the end.. Probably not.  To have the export feature [more so] work in-your-favor and "Less chances of them not working and less headache"? Most likely.

That's all dependent on the core being used for that system.
 
Just looked back up at your RetroArch screenshot. For some reason Remove Quotes got checked.  Un-check that.

The error indicates something is up with your license file. Email support@unbrokensoftware.com and they can sort it out for you.

If you have the ROMs/games loaded into RPCS3 already, you can turn on the Auto-Import feature for the platform and LaunchBox will read RPCS3's virtual drive and import those games.  So in this instance, no. It doesn't matter where you store them.

View < Media < Refresh All Images

 
Alternately, you can click on one of your PS2 games then press Ctrl+A (to select all games).  Then press F5 to refresh images for selected games.

In that case, in LaunchBox, Edit the game you want to change the default version to be played when you click Play.  When editing that game, go to the Additional Apps section [for that game].  There you'll see the different versions of that game.  [Single-]click on the games' version you want to set as default.  On that same screen, click Make Default [located on the bottom right of that screen].  Click OK to save and close the edit window.  Now when you click Play, that version you selected previously and had clicked Make Default for is the version that will be launched.

Auto-Save, 'Manual'-Save and Quick-Save are separate Save States.  The Error is trying to load a Quick-Save. (vs. creating one)
Open MAME (mame.exe) and go to General Settings < Input Assignments < User Interface and look for Save State to see the assigned keys for saving and loading States.
[The default] to create a Save State is F6.  (To create a Quick-Save, it's Shift+F6.)
[The default] to load a Save State is F7. (To load a Quick-Save, it's Shift+F7.)
 
Here's the 3 different Save States

"1" is a "manual" Save State. (I believe can be a number 1 through 9 [1 through 0?].) 
"auto" and "quick" are self-explanatory.

Oh snap!  I was thinking save states.
For per game configurations, you'd use  -cfg_directory "
D:\MAME\mame.exe" nes -cfg_directory "D:\MAME\cfg\nes\addfam" addfam Or
nes -cfg_directory cfg\nes\%romfilename%  

Correct.  BigBox is not setup to manage your games.  Just looks pretty and plays games.

Looks like I missed saying to uncheck the "Remove quotes" and also the "Remove file extension..." boxes.  Srry 'bout that.

In FinalBurn Neo: Misc < Configure ROM paths...    Set the path to your ROM folder(s) [if not already]. In LB, edit the emulator and check the boxes Remove Quotes and Remove file extension and folder path. At least that's what worked for me. I got the same error with those 2 un-checked.
 

Un-check Remove Quotes.
Also, add --nogui to the Default Command-Line Parameters.

MAME is for Arcade games.  Appears you had imported them into the Windows platform (vs the typical Arcade platform).
By default, LaunchBox sets the metadata/media scraping for Windows platform to Windows [PC Games].
If you wish to keep your Arcade games in the "Windows" platform, edit the platform and set the Scrape-As value to "Arcade" and re-scrape the metadata/media.
A more prudent approach could/would/should be to remove all the MAME (Arcade) games from the Windows platform and then [re]import your MAME ROMs into the Platform "Arcade".  Then when you download images, you'll get the ones for Arcade games and not PC Games.

I'm fairly certain your "mame64.exe" is from an older version of MAME.  Being older is not the issue (and nothing to be concerned with). 
However, having the command-line parameter -keyboardprovider dinput would be an issue with older versions.
Edit your MAME64 emulator ('Edit/Bewerken' from screenshot above) and try removing that and see if it [now] works. 

If it's showing when LaunchBox is first being started (aka when 1st launched/loaded), I'd say LaunchBox is [still] attempting to load an eXo ('exodos stuff') remnant.
Assuming you're starting it via LaunchBox.exe (vs. a batch file or script), look in Tools < Options < Startup Applications and see if there's anything eXo related.  If there's nothing in there, I'd next look in the /LaunchBox/Plugins/ folder.  Not sure exactly what would be 'eXo' there.  But those 2 locations should/would be the only places LB would start something extracurricular (aside from a batch file or a script that starts LB).

If, when you disable G-Drive syncing and you're happy with how LaunchBox/BigBox performs via G-Drive (which I guess at this point is actually running from your local G-Drive folder), then...
 
A variation of a Google search result looks like this:
This link mentions "googledrivesync.exe" which is now "GoogleDriveFS.exe" (at least on my PC). It seems there's no command-line parameters you can pass to the executable to turn G-Drive syncing on/off.  So you have to "kill" the process. From the Windows Command Prompt, to kill G-Drive altogether, you can run taskkill /IM GoogleDriveFS.exe /F Then to restart it, double click "GoogleDriveFS.exe".  Mine's located in "C:\Program Files\Google\Drive File Stream\100.0.2.0\"
 
LaunchBox/BigBox has a Startup Applications feature that can load an application when one or the other or both (or neither?) are started. (Which could be a batch file containing the above command.)
But there are no (immediately accessible) means to launch an app when either close.  "Immediately accessible" meaning, you could create a plugin that captures the System Event LaunchBoxShutdownBeginning and/or BigBoxShutdownBeginning and then (re)start the process "GoogleDriveFS.exe".
 
Alternately, you could create/use a batch file that handles the whole kit-and-caboodle.  Something like this (edit accordingly)
taskkill /F /IM GoogleDriveFS.exe timeout 5 start /w "" "D:\LaunchBox\Core\LaunchBox.exe" start "" "C:\Program Files\Google\Drive File Stream\100.0.2.0\GoogleDriveFS.exe" Do This:
Verify YOUR Google Drive executable is indeed "GoogleDriveFS.exe" Change the path to YOUR LaunchBox location DO point to the /LaunchBox/Core subfolder Change LaunchBox.exe to BigBox.exe if that is your preference Verify that is the path to YOUR "GoogleDriveFS.exe" If all's good/tested/working, make for a 'prettier' presentation...
Create a shortcut to the batch file Right-click the shortcut and select Properties Change Run from Normal Window to Minimized Click OK to save and close. Use the shortcut to start the "whole kit-and-caboodle".  The above makes it so the Command Prompt window does not appear.

The only times I've seen this happen is when I launch the game, and it's the 1st time Steam has been launched (on that particular day), and Steam has an update.  Steam will do its update thing and then show the "On Sale" and 'Main' windows.  This happens in the background, so you don't see anything when the game [eventually] starts, and you play it.  It's when you exit the game you see those windows still lurking [on top of BigBox].
I've gotten in the habit of, before I start BigBox, if I know I'm going to be playing a Steam game, I'll
Start Steam 1st.  Let it do its thing close/minimize Steam when it's done then start BigBox.

For this, you'd need to create a plugin (written on C#).
Essentially, it'd catch a selection change event, determine that the change went into a playlist (vs say a different game, a platform or a platform category) and that the playlist is 'your special playlist'.  From there, execute what you wanted done.
 

In your Flycast emulator folder, edit emu.cfg and set fullscreen to yes. 
[window] fullscreen = yes  
In LaunchBox, edit your Flycast emulator. In the Running Script put:
$Esc:: { WinClose, ahk_exe {{{StartupEXE}}} }