So. I'll have a stab at DRRR!!, my current obsession:
Izaya - AWESOME.
...oh, what's that? I was meant to be typing him?
INTJ, first off. (Oh yes, yet another INTJ anime antihero/antagonist, complete with chessboard to represent his ominous/epic master plan!! XD)
Enneagram 5[w4?]: amassing knowledge and understanding people is what he does; observes "humans" from the position of outsider-looking-in; adopts an attitude of careless, fuck-you-all superiority to render himself invulnerable to the threat posed by others.
And Sx/so: intense, iconoclastic, very counterphobic (I mean,
what could be more counterphobic than his endless provocation of Shizuo?!), arrogant and at ease in/okay with most general social situations [unlike other 5 variants], determined to make a mark on the social sphere. But there's also a sense of deep, latent insecurity in him: probably comes from the groundlessness of Sx/so without any anchoring close relationship, and also that 4 wing.
Shizuo - ISxP 9w8 sx/sp. Aw, bless him, with his strident 9-ish hatred of violence all conflicted with the forcefulness of the wing...And he at once has a dynamic, charged presence (does he ever!) and a kind of lonerish vibe to him, which IMO makes him sx/sp without question.
Celty - INFP, 4 sp/sx? She does spend the whole series "searching for her head" (read:searching for a coherent identity), after all

Initially she seems aloof, cold even, but beneath this holds a deeply-felt sense of values: INFP. And sp/sx for this marked gulf between the restrained, "together", assertive dynamic to her interaction style that seems very sp-first, and close one-to-one relationships with those she feels really understand her, suggesting sp/sx.
Shinra - ExFJ...? Gah, I dunno. He's too crazy to type XD
Kida - ESFP 7w6. And sx/so LIKE ANYTHING.
Mikado - ISFP...6, maybe?
Anri INFP 9w1 sx/sp? The being unable to draw clear boundaries between the self and other, the whole idea of being a "parasite", "feeding" off another's energy/selfhood, feels very unhealthy/insecure 9. Of course, the existence of Saika makes it kinda hard to type her, but she feels roughly sx/sp.
Saika itself seems to be a symbolic configuration the Sx instinct, gone about as wrong as it can go.