Re: Do you think the Red Skull will return?
I don't think Skully will be a part of CATWS at all, but I wouldn't be surprised if he's teased in the post-creds for Cap 3.
My own personal theory is that Skully went to the part of the galaxy that Thanos calls his throne at the end of CATFA, and the post-cred for CATWS will show him as Thanos' servant, getting ready to visit his old pal Steve for Cap 3.
THE COTTON AVENGERS
...They move like slick cotton on oil.