I wouldn't call Marin "fair". She was a brunette and I didn't notice on my tv that she had blue eyes. I don't like that plot twist either, but not for that reason. Julain and Heather look like they could be related to one another, but neither looks related to Jack, frankly.
Marin says "He" is the father when she tells Vera she is pregnant. We are to assume she means the Beacon, but she doesn't say so.
And I guess we are to assume Vera killed the Beacon, even though she says he just slipped away on his own.
This is my problem with the show. They do all this twisty-turny mystery