Regarding Wolf's voice, note that all characters who got new voice clips (be them from previous VAs or new ones) did so because they needed new voice clips.
The only veterans who got new voice samples:
- Orbital Gate Assault conversations
- New Final Smashes
- New Copy Abilities and new Final Smash
- PK Freeze
- Palutena's Guidance and new Final Smash
- New Final Smash
It seems to me that, unless really necessary, veterans keep the same voice clips as previous games. The only exception is Sonic in the English version, but he's a third party so Nintendo doesn't have control over his voice clips. Sega does. And even so, his voice clips are recycled from previous games.
Kirby and Dedede got new voice clips, while Meta Knight kept those from Brawl. Meta Knight had no changes to his moveset to justify needing new voice clips for him.
The same could happen with Wolf, as I don't expect any major changes to him. Besides his Brawl VA never voiced him in any Star Fox game, so it's basically his Smash voice.
Since Orbital Gate's conversations aren't actually done by Fox and Falco, but by holding down a button upon selecting the stage and scripted for its progress, there's no room to make new conversations for it.
The only place where Wolf can have conversations is Lylat Cruise and those are ported from Brawl.
Of course, I'm just speculating. But considering precedence, I think it's likelier for Wolf to keep his Brawl voice than getting a new one.