I think post-end expansions might work. If we look closer we see, that story in a video game is not really about Geralt but about prophecy of White Cold and Wild Hunt. Geralt (and lot of other characters) just got it right time in right place.
So now Wild Hunt is kicked out of scene and WC is.. well, whatever your ending is, Geralt live his own live, but it don't bound him to one place. He can still hunt monsters and visit old friends. Universe continue to live as it was, story of Geralt and others is principle go on.
So, my opinion: Shani can be visited at field hospital even after "game story" is over. Old places (like Vizima) could be included.