Along with other related quotes that I am too lazy to quote all of; just the general idea that she could come back someday...
People have said that Coco and Aloe have invites to come back whenever they want, does that mean 1. They can sign a new contract and come back to work, or does it mean 2. They can appear as a cameo if they'd like to?
Because even though it'd be so short after she left, I could imagine Sana coming back for a Council 1st anniversary stream, or at least like a recorded video cameo. Obviously not under a contract, but just "Hey, you were (probably) involved with the planning and merch and stuff for this, so if you want to show up to say 'Hello' you can."
Edit:
Fauna is surprisingly internet/meme savvy, I wouldn't be too surprised about her knowing all sorts of random stuff.