Ash-Greninja Return?

With the Home update, and the very near release of Pokémon Champions, I was hoping that Ash-Greninja would return for the games.

I brought mine to Home, from my Ultra Moon save file and I heard that it wasn't available for Scarlet and Violet. I was worried that it would change the data of my Greninja to remove it's unique transformation from it. However, I figured with the rerelease of Zygarde that maybe I'd be able to send my Ash-Greninja to Legends Z-A, since they both changed forms the same way. (Through battle damage.)

I assume Pokémon Champions will for sure bring Ash-Greninja back since it will basically be attempting to add all Pokémon back to the overall roster for the newer gameplay. But, there's no formal confirmation on any of it.

I also don't want to risk losing my Ash-Greninja, so I'm hoping for some confirmation, before attempting to move him over. He's been stuck in Home for quite sometime. I'd like to have him join my journey once again. Maybe even have him face Mega Greninja at some point.

Side Question: For clarification. Will my Pokémon be able to transfer forward from Legends Z-A, into future games or will they be stuck there? I figured they'd be transferred forward, but a lot of back and forth discussions have gotten me concerned. (I am aware they can't be transferred backwards, sadly. But, I'd very much would like to keep certain Pokémon part of my journey forward into the unknown expanse of the continued Pokémon Universe.)

P.S. I hope I put the proper category and stuff. First time making a post.