let's type some of the characters...
Christian Troy: ENxj... Peter thought maybe ISTj. I can see why he could be seen as a Se type, but I don't think he has genuinely strong Se.
Sean Mcnamara: I'm stumped. He seems to value Fi and comes off like a Fi type in some ways... but he's SO stupid when it comes to Fi matters. In my mind right now he could be pretty much any type. Something about him seems Delta, but he's Christian's best friend, so I dunno. If Christian is ENTj, it could make sense.
Julia Mcnamara: ISFj
Liz Cruz: prolly my favorite character... INTp
Kimber Henry: IxFp
Matt Mcnamara: another mystery... some ethical type
Megan O'Hara: INTp I think... maybe INFj? It's hard to tell because we meet her during a life crisis.
Merril Bobolit: ENFj?