Yeah too many people seem to be operating under the assumption that the upcoming series will be structured like a traditional 26-episode tv season/65-episode syndication setup, which is very much not how a lot of tv works these days. It’s a pretty safe bet that it’ll remain on a streaming service of some form, since that’s where the money is, and it gives the show producers a hell of a lot more flexibility when it comes to episodes. It also means that VAs aren’t as comparatively expensive since there’s less episodes which are easier to budget in advance for VA expenses.
Centaurworld, Rick and Morty, and Invincible are better examples of what we’ll likely expect in terms of episode numbers and VAs, so VA affordability and availability are much less of an issue.
Yeah recasting the VAs for the mane cast would be a terrible idea for the show, as it would make the show feel like a soft reboot of g5, and would strangle it in the crib. It would be a shame, because the people behind the movie appear to have a genuine respect for the property, the intelligence of its fans, and what came before it (g4).