The recent updates have finally allowed me to get this working in Project64 (you have to turn off the controller when booting up, then turn it on after loading a game), but the trackpad and gyro are pretty much useless so far. In Xinput mode, there's no real option to adjust the stick sensitivities and the trackpad and gyro end up being very jerky and unresponsive in mouse joystick mode as a result. You'd pretty much have to crank the minimum output value up to max to get smooth movement, but by then it's so fast and insensitive that it's much less precise than the analog stick.
I tried Kb+mouse mode and it seemed to have potential to work when using the analog stick/trackpad/gyro as a mouse with absolute input. You can walk forward with analog input by holding the stick forward. The problem is that it only works for several seconds before your center point is lost and everything goes haywire.
Has anyone else used this with P64 and gotten good results? I don't know if a different controller plugin would resolve this issue or not. If nothing else, I can use it just like a standard pad without the trackpad or gyro, since the analog stick is much, much better than the one on the Wii U Pro I normally use, but it's kind of disappointing to settle. I imagine it'd be a lot of fun to play not only MM and OoT with gyro+trackpad aiming, but Goldeneye and Perfect Dark would be really fun to try too.