The problem with the Unova squad getting redemption is that I doubt the writers will even bother with them. The series has been a nostalgia/popularity fest so far, so why bring back Palpitoad or Boldore when you can bring back Charizard or Greninja? At best we'd get Krookodile and the starters back, and even then I don't count on it.
Considering that they have no problem bringing Chuck back even though there are way more popular and more well known characters, I don’t think you can really count some of Ash’s reserves out just because they aren’t as popular as some of Ash’s other Pokémon.This is unfortunately true. Out of all the Saga squads, Unova is basically the most forgettable along with Johto and prob the most unlikely to even be bother to be brought back. They likely very well still do remember they exist but even with that, it’d be a miracle if they’d even bothered bringing them back, even for some battles considering they were really bad.