I don't think so. The Branded blood shows up in some of the descendants, not all. Even Stefan says that in the info convo.
If all the children of a Branded would be Branded, then wouldn't
father and some other relatives join him? Wouldn't they all be shunned for it?
Maybe the Begnion empresses are different than the rest for having strong blood or something. Or maybe we aren't told about all of their children. Actually, it's really possible that Sanaki isn't a Branded. There's nothing indicating she is one, as far as my knowledge goes.