There are not any compatibility lists at the moment. Your best bet is to look at the RVLoader GitHub issues section, some games have been reported there. If a game flat out doesn't work with GC2Wiimote (Doesn't register the controller as you mentioned), please make an issue there so Aurelio can look into it. You can also find a list of Wii games that use traditional control schemes here
https://en.wikipedia.org/wiki/List_of_Wii_games_with_traditional_control_schemes
You can also find the input methods supported for each game on Dolphin's game tracker:
https://wiki.dolphin-emu.org/index.php?title=New_Super_Mario_Bros._Wii
The mii import app currently doesn't work as far as I'm aware. You may be able to use a homebrew to modify the Miis, I'm not sure. I believe Aurelio has fixed this for the upcoming RVLoader update, but don't quote me on that.
The Wii menu goes black because of a regression in RVLoader where the VGA patches needed for the screen to recognize the video signals no longer are applied in the Wii menu. The modder you purchased from did everything correctly as far as that goes. It may be fixed in a future update, I'm not sure