So I just tried a bunch of games in Mii Maker mode (I don't own Smash Bros) and I can confirm that Captain Toad Treasure Tracker EU works, Kirby and the Rainbow Curse/Paintbrush EU works, NES Remix Pack US works, New Super Luigi U US works, New Super Mario Bros U US works, Nintendo Land US works, Scribblenauts Unlimited works, Scribblenauts Unmasked works (listed as untested on the sheet), Wii Sports Club works to the Wii MotionPlus required screen, but since I don't have a wiimote with MotionPlus I can't test further. Game and Wario US does not work even though it says it does on the sheet, if someone did get it to work I'm really interested in finding out how as my brother really wants to play that game. Donkey Kong Country Tropical Freeze EU does not work, and neither does Yoshi's Wooly World EU. Once it's done downloading I'll test Rayman Legends as well.
Thanks for the great work!