Neither new character is a CS child. Just read the character descriptions. The man is clearly Henry, and that is his kid (whether adopted or biological). A&E aren’t going to put some random person like Prince Neal or an unborn child as the star of a new season. They’re going to put Henry, who is the author and central to the story going forward. He isn’t going to be taking care of a potential half-sister. It’ll be his daughter because A&E love to have things come full circle, and Henry will have to form a connection with his own child the way he and Emma had to in season one. They just like their circular story telling and parallels too much to write it differently.
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy