This is an interesting battle. On the surface, it may seem Phoenix's versatility could be too much here. However, he's got one fatal flaw:
He's really not a great fighter in terms of combat intelligence
Because of that detail, it evens things out, since She-Hulk is definitely a better combatant, and even has the advantage of what's essentially a ranged option Phoenix can't reliably counter given its sound based. Phoenis has a slight AP advantage and can even boost that with X-Factor or Turnabout Mode. I think a lot of Phoenix's success may come down to if he can manage to tap into that state, which in his case, won't be easy. He has to look for evidence after all, and Maya can only provide so much in terms of defence. Nothing's stopping She-Hulk, especially with the giant ass leaps she can make, from closing the distance and ragdolling him. Questioning may be able to stun her briefly enough to pick up some good evidence assuming Wright lands it in time. He's also got too different methods of healing, one of which does so passively. Order in the Court could provide Jennifer with some trouble as well. But really, I feel that Phoenix's best chance at winning here is negotiating with her, given how he talked down Galactus. Otherwise, I feel its more likely She-Hulk overwhelms him with her superior LS, experience as an actual fighter of sorts, and harder to counter ranged attacks (Thunderclaps)
Voting She-Hulk