GH4 and GH5 are both full-band games.

I honestly don't know enough about music to answer your mic question very well. There are a few songs where I seem unable to get a low enough tone, but it's not very often. I don't know any guys who can't get high enough, though you may find yourself singing like a jackass for a better score one in a while, heh. The octave displacement issue does come up from time to time, but it really hasn't hindered me from enjoying and of the games.