Yes, the full core package is the one from latest Lakka build.
are you using provided categories.xml file? did you try the roms you are trying to launch with AEL with RetroArch? do they work?
Also, before first time launch with AEL it is recommended to launch retroarch addon one time to set up and permissions.
After I configured RetroArch and tested the games there, everything worked smoothly in Advanced Emulation Station. Thank you for the guidance!
When I press Start + Select on the controller inside one of the games, the RetroArch menu pops up. Is there any easy way to change this so that Kodi is started directly instead?