Well, i think scott is an defintly a negative sterotype of the ESTP in the book, being a bit of a player ass-hole, however I think towards theend of the book & in the film he grows emotionaly & becomes an Esfp, realing & apologisng for being mean in genral to all his exs/gf's.
Ramona I think is either an INFP or INTP depending on her state of mind.
Kim defintly an INTJ :')
Wallace shows some F traits ( he tells scott to break up with Knives before going out with ramona, possibly with the intention of sparing knives pain) but his is probally A ENTJ.
Knives Chau <3 though she seems pretty dense at points, in the book she fully acknowledges she can't be scott quote early on on, but becomes obsses with with his happiness, aswell as creating the scenorio in her head that ramona stole him from her, suggesting she is an INFP, having a jealous streak, virtually unselfish love for scott ( particulary right at the end of the film, where she loves him enoughtt o let him go) & a very active imagination creating scenorios in her head aswell as only having really only one friend ( I see some of myself in her to be fair as well as wallace when I'm drunk :')) ^_^