I have only just started watching this, so go easy on me with disagreement:
Ben: ISTp, very clear awkwardness with Fe
Brother Justin: archetypal, unmistakable, unequivocal and unnegotiable ESTp
Iris: Edit: I call her ISFj. A candidate type changer from INFj to ISFj through the story. The relation with Justin is far from exclusively positive.
Samson: ESTj, pretty sure on this.. a "communal problem solver" neg-Process Ej as contrasted to Clayton and Ben
"Jonesy" Clayton: ISTp, an agressive version, very clearly Pos-Result and Tac-Aristocrat power tripping. Also not ISTj due to the lack of self-control.
Sofie: Re-Edit: I have come to see her as more of an NF type now; she is extremely elusive type wise due to the general effacedness of her personality)
Lodz: Edit: Nope, not ESFj. He's the other Positive-Result Fe type: INFp.
Lila: Edit: INFj is more likely than ISTj, she turns out to be softer of charcter than I first thought she was
Ruthie: INTj; though I've seen too little of her to be sure
Stumpie: some extrovert judger, ESFj is a good bet
Rita and Libby: Extroverts, probably both ESTp
Gabriel: not much of a personality to analyze.. otherwise, another ISTp
The rest are from episodes I haven't seen yet.