Cad omg if they added Va for the games that would be legit. For a company like Pokémon, I think they do have enough money to pay voice actors.
I think it will be something along the lines of Yellow/Crystal/Emerald/Platinum where its just an expanded version of the previous games with some minor changes and added plot points. That being said, I'm definitely open to the idea of a completely different alternate story-line.
My theory for this game is that it is the alternate universe you can travel to in the first game at the top of the Altar of the Sunne/Moone and since you took the cosmog from that universe it caused some sort of universal unbalance and caused Necrozma to infect Solgaleo and Lunala.
I have some ideas of would could happen for alternate versions of characters. When Gladion left the Aether Foundation, he founded Team Skull to fight against them and Lillie serves as his second-in-command. Guzma is your rival. Plumeria runs the day-care. Hau is trying to open his own Malasada shop and not interested in taking the trials. Molayne is still a trial captain instead of Socrates. One of the islands has a Pokémon as its Kahuna. Acerola and Ryuki have major recurring roles throughout the plot. And you fight your mom to become champion instead of Professor Kukui.
in the last games, Lillie sort of tagged along as a protagonist. We knew her story of how she took Nebby and learned about Gladion on the way. I think it would be cool if it was the reverse this time around where Gladion accompanies us instead. That would make Nebby more mysterious and would build up the story more for when it evolves and potentially fuses with Necrozma. Maybe Guzma would be a bigger deal too? It's a little strange how his name is so similar to Necrozma's. Maybe this time he does end up being the main villain?
This would be very cool. Seeing them all trying to achieve different goals would make it so real for me that it is an alternate story.