okYou Know Mania was ported to the Wii U through the homebrew scene right?
And then in addition to the native Wii U Sonic games and the other decomp ports you mention, you can use emulators and loaders to play soooooo many Sonic games on a Wii U (to the point where it would be quicker and easier to list the Sonic games the Wii U can't play lol).
thanks