Even a Star Wars fan like me just heard about Chewie's death. I don't know how he died in the books. I don't know anything. It's almost like a rumor to me. So of course Chewie is alive for the general public.

The only thing that could make JJ not using Chewie is that Peter is not in good shape these days. So maybe JJ could say something like "Hey, Peter can't do Chewie anymore. Do we really want someone else instead? If the answer is no, then let's do as in the novels. He died long ago."