Sakuraba, you need to chill, and stop calling people idiots. Your arguments are not perfect either (but you do have some valid points). The more you talk, the more I start to think he could be INFP (although your points on ENTJ are still pretty good... it's a toss up for sure).
Why the hell are you trying to compare Amy Lee to Tupac as proof Tupac isn't INFP when they come from such radically different places that even if they were the same type they would be radically different anyway. I think it would be better to do some comparisons with some other rap artists, especially INFP and ENTJ ones (i.e. the RZA is a classic ENTJ, but he doesn't really seem that similar to Tupac to me based on what I've seen).
YouTube - Tupac Age 17
Thats Tupac when he was 17. If that isn't NF, nothing is.
YouTube - Tupac Interview
Another one where he shows some very NF like characteristics.
Yes, Tupac didn't have it
that bad but he still had it pretty bad (too poor to go to college despite being highly intellectually gifted, and being surrounded by other young black men who could also be going to college if it wasn't for being poor, hopeless, helpless, and surrounded by drug addiction and violence. Tupac was certainly exposed to all that and saw it every day and recognized the problem. The problem clearly bothered him a great deal. Even watch those videos you linked, he has that kind of NF fire and passion to his cause.
If having Fi is his inferior function coming to the surface as ENTJ, isn't it just as possible that all of your points are his Te inferior function coming to the surface as an INFP? I think that makes just as much sense, personally (which is why I'm on the fence right now).
A lot of those things he said ("against all odds", ect) could be said by any intelligent person in his situation -he was against all odds; he lived surrounded by poverty, drug addiction, abuse, corruption, ect. He did go against all odds. "Fuck the world if it can't adjust to me" could be identified as INFP stubborness, as well. I've probably said that myself. It's by no means an exclusively or even dominantly ENT thing to say.
As for never seeming depressed or melancholic, on one hand thats a bit of a stereotype and on the other hand some of those youtube clips from the documentary seem to show he may have experienced that to some degree (i.e. "he began to lose a lot of control"... he began going deeper and deeper into the anger and everything rather than thr sympathy some of his earlier stuff has... could be classic Fi). I only saw some short clips, but they certainly showed the capacity for a lot of anger, depression, ect.
And as Dissonance said, NF's are not neccesarily co operative. I know in my own experience I've been very stubborn, very against the grain, very uncooperative, ect, for the sake of trying to achieve some kind of change or improvement (although never about anything as big or important as Tupac, but I'm also not exposed to anything like he was on a regular or even infrequent basis). NFs are definitely not neccesarily cooperative though. Even the whole quest for harmony thing fits well with Tupac; he neer had harmony, he was always surrounded by turbulance and chaos and it stressed him out, it threw him off. Thats what those speaches linked in this thread are all about, especially the 1992 one, I'd say.
I think everything he did certainly fits the INFP catagory in some respect, at least as well as ENTJ.
What I find fascinating about this is the difference the inferior function is making here. It seems to me that he is either an ENTJ with a well developed Fi function or an INFP with a well developed Te. The inferior usually isn't the dealmaker in typing people...