Kristoph Gavin:
He didn't befriend Kristoph at home -- Edgeworth has done that. The public opinion is that Kristoph has replaced Phoenix as the one defense attorney Edgeworth will be civil to.
The only one he's actually interacted with was
creepyface_esq. (That's actually a one-shot crack Kristoph, but Phoenix only saw him for a few minutes, so the crackiness wasn't an issue.)
After meeting creepyface-Kristoph, as I said in chat, he had that recurring nightmare about the night he found Mia's body, though by himself, not in the night-terrors room. (I've written it up just to have it for reference but I'm not happy with the prose.) In that case -- it was Edgeworth's body, and Kristoph taking Redd White's place. He's likely going to have that dream a lot in the DR.
He now has confirmation that Kristophs are not nice people, which he'd suspected, but he hadn't realized how far Kristoph would go. He thought the forged evidence was the whole of it -- he never suspected murder. (He knows the truth now.)
When he first got to the DR, stalking Kristophs was high on the agenda. Now he avoids them.
Klavier Gavin:
He didn't think much of Klavier at the trial -- arrogant rookie, more committed to music than law, etc. Edgeworth works with him, and is generally annoyed by his attitude, but can't find actual fault with his work when he shows up. His opinion is really sort of similar to Ema's -- deep annoyance, but some amount of trust.
He always refers to Klavier as "Prosecutor Gavin" to differentiate him from Kristoph. (He'd feel a little weird using his first name unless specifically invited, since he barely knew the man at home.)
He's met two in the DR:
einspruch_baby, who gave him most of the 4-4 story. He was surprised to find the man friendly, honest, and really enjoyed speaking with him. He trusts him now more than just about anyone else in the DR.
He also spoke to
einspruch, which was a somewhat awkward conversation -- Phoenix was feeling guilty about misjudging Klavier, and was misreading this Klavier a bit, so it was strange. But it reenforced his opinion that Klavier is honest and a good lawyer and had nothing to do with planning the forgery/framing.
Edgeworth:
The only Edgeworth he's spoken to in-depth was Hoboworth. He doesn't know exactly what happened to that Edgeworth -- something went wrong with von Karma, and he does blame his alternate in that world a little -- he's assuming that perhaps von Karma was indicted for the Hammond-frame but that Edgeworth still thinks he killed his father, or something similar. The conversation took a turn for the snarky, though, which reassured him that Hoboworth, for all his issues, was at least holding on to his wits, and that only time could probably heal him.
Dahlia:
faux_twin was one of the first people he met in the DR -- she freaked him out. He loved Dahlia, though, so depending on the context, he may be too willing to give them the benefit of the doubt.