Drawing tablet is fine to use! The only thing we disallow is the use of more than one clicking method - for example clicking with both the pen and the mouse simultaneously.
Just my notes regarding the findings above: Emulators do not need to use a microphone, and can instead use a hotkey. Console disadvantage.
Mouse is faster due to fast clicking methods. Console disadvantage.
Tablet can be used to mitigate issues with swiping motions, and we've already had people using them. Console disadvantage due to lack of choice.
Haven't personally tested loads/RNG yet, difficult to test with console consistently. To be determined.
Cheating is possible with Emulators, but we do what we can to prevent it.
Overall the emulator has many more options and advantages. I would fully endorse splitting the leaderboard, since the lack of an even playing field could dissuade console users from attempting to beat existing times.