I just saw this movie.. I absolutely loved it. She's like the poster child of ME.. it's uncanny. But his suffering over her is very similar to what I've experienced in the past, though, for someone who I felt was "the one". I really did feel for him deeply. I wish I'd seen this movie back then. it kind of put it all into perspective in two hours, which in real life took me about 6 monthes. Anyway, as to type:
I definitely agree that Summer is INTP. I don't see any way at all that she could be INTJ.
As to Tom, I can definitely see the NF in him. Past that, i can't tell. I almost felt like he was an ENFP, but purely out of comparison to some I've known. He was utterly fascinated by her and wanted to delve into her soul. I'm just not sure though.