Just uncheck all the media options except for the metadata when re-importing. You are right media is not deleted and is still there, but unless you unchecked those download options you are telling Launchbox to download it all again, so you will have duplicates of everything.
Yes that is incorrect. All the roms will be "standalone" in a non merged set. So each rom will have all the files needed for the game to run, so you will still have all the parent/clones just that each file will work by itself and not rely on files in the parent. You will about double the size of your set if you convert it to non merged as you will be duplicating thousands of files into other zips rather than the current way of the files in a zip being shared amongst other games. your set will go from about 60-65GB to about 120GB, and it will make zero difference in Launchbox.
File name or name in launchbox DO both work. If you download videos from emumovies from within Launchbox they are automatically named the same as the game in Launchbox.
I would never recommend killing native PC games like that. There is a reason PC and console games have warnings to not exit/shutdown your system when the save icon shows. Just killing it with alt F4 (which is what Launchbox will send as escape wont close most PC games) you risk corrupting your save games. Always close PC games through there in game exit menu's.
Thats fine, i have a roms folder and a CHD folder myself, but as long as MAME knows where they are you can have them anywhere you like, even mixed together if you wanted.
Thats about right. you dont have 37,500 games, you have 37,500 files, big difference. Launchbox with the default fullset importer options only imports working games.
In Bigbox go to options/image cache and "refresh platform logos". Also its worth noting the logo must be named exactly the same as the platform is named in launchbox/bigbox.
Launchbox doesnt have a "core list" the dropdown just shows the cores you have in your retroarch/cores folder. So if a core isnt showing, you dont have it downloaded in retroarch.
You really think a ARM based notebook will be anywhere near as good as a desktop PC? That's dreamland you are living in there. Somehow i dont see a ARM based GPU worrying my RTX 2080 Super any time soon.