I would think it's a Gorillaz Mini, because it's in a Gorillaz fic. It was mentioned at some point earlier that a misspelling of the name of a city in France in a Les Mis fic would make a Les Mis Mini, even though the city is also a real world location. It seems to me Gorillaz would follow the same logic with the real performers its universe "borrows."

I also like Barid's and Miah's ideas, too, though.

I think I once it saw suggested that real people minis should be something unlike their real person counterpart. The ideas I remember seeing were mini-movie cameras for actors, mini-microphones for singers, etc. YMMV.

Since Tupak was a real person, misspelling his name would create a real person Mini. However, since you are in a Gorillaz fic, it could be a cartoon version of the real person in question.

... If I remember correctly, usually the first to find a Mini in a Continuum decides what they look like. Or don't they?
Anyway, maybe the mini is half cartoon, half Real World, seeing as the Continuum seems to be both, from what I can guess from your post? (I don't know it, so no idea.) As to what kind of Mini... No idea there, sorry...
I hope this helps somewhat, at least...