I don't get an incest vibe. I read later that there was a pseudo-spoiler that said the Betty Applewhite storyline would be something rarely touched on television, and people speculated that it would be an incestuous relationship.
I think a lot of people's impressions are born from that speculation. I didn't see anything kinky or weird like that. I also think Alfre is entirely too good an actor to accept a role that would make her an incestuous woman on a hit primetime drama/comedy.
If there is a relationship, they are not related, but as I said, I don't think there is a relationship there at all. I didn't pick up on that, in any case.