About T.O.P.... I think he's INFP or ISFP. He comes off as super mysterious and silent but if you see his backstage moments and his jokes he is literally crazy xD Also he admitted on Strong Heart that he is very, very mischievous and he doesn't know why people think he's so serious.
I think he tries very hard to keep the spontaneity suppressed but he's started letting it out more these days because he's coming to know that people like it.
Definitely Fi somewhere there, he has very strong ideals and it's always all about him. In his interview he and GD were asked what they'd do if GD&TOP were nominated against Seungri for some award.
GD: In that case, I think Seungri should win...
TOP: No, Seungri can win later. It's two against one and we should win.
The spontaneity is either Ne or Se. Likelier Se. He acts like a 5 year old. He even goes on slides for kids and you should see his face while on a rollercoaster.
He got an iPad and he posted pictures of himself using Photo Booth, lol. He's crazy and doesn't care much.
Not ISTP because the Fi is so overwhelming (and the Ti nonexistent), you should see him when his words are disagreed with or when he's offended. He puts up a nice face, but he's angry, really angry.