You go ahead, darling, and I will 100% them all! Muwahahahaha.

Okay, let's get serious. I don't really think JJ songs are good material for GH/FoF levels. Sometimes it will be hard to determine a melody, and the constant echoing of the existing melodies may very well confuse the player, as he hears a lot of notes twice. Accurately making these tracks will require you to make a difference between echoes and actual notes 'played on the instrument'. If you need an example, take a look at the intro of F.C.P.R.E.M.I.X. from GH3. That demonstrates clearly how echoes and notes should look.