Parry, I think, is definitely bent -- although I can't now quite think of what my evidence for that was, other than (a) him obviously warning Terry off when their paths crossed at Alpay's, and (b) him saying to Tom early on that he had 'put Evan in touch with some criminals'. At the time it sounded like it could be just that Evan wanted to get into more criminal defence work, but I think that in retrospect there's clearly more to it than that.
Tom -- also at least somewhat dodgy. I think he knew what he was looking for when he went to find the Pedersen documents, and he excused his shredding of them to the rest of the firm as just being an old client of his.
DI Williams -- differently dodgy. I think my earlier expectation that her professionalism would lead her to take Faith's part, albeit reluctantly, has now clearly been disproven, but I don't think she's in with the same lot as Parry. I half think she's just flawed and lying to protect herself, but I do suspect there's a bit more to it than that: on top of her old enmity with Faith, there's the whole question of DS Morgan, and who the bent copper was that Alpay was going to name.
I don't know who's bankrolling Arthur. I'm still open to the possibility that it could be Evan...