The mom from Y3DF's "Circle" was a skank, anyway, and while I would not use that exact description for Alexa, though I'm not particularly content with the events of this latest Chapter, she has always been portrayed as having a preoccupation with incest, so I think this could explain a lot, although I would've hoped that her attraction toward Liam was just projection of a secretly held attraction she has always had for her own sister. I don't think their father, Amanda and Alexa's that is, would fit into the story this late, but if it were a "one-shot" prequel of how she almost hooked up with her father, I think that might be an interesting read.
I don't think Lana will divorce Alex. I think she'll feel less guilty about cheating on him with their son. Alex is more valuable to Lana and Daniel's "secret" relationship, being married to Lana, than he is divorced from Lana. He provides the perfect cover in case Daval decides to go the pregnancy route. I also don't think most of the audience, myself included, would want to see Alex with Sharon, especially before Daniel and Sharon. With that said however, I also don't think most of the audience, myself included, would want to see Daniel and Lana with anyone but each other, Alex notwithstanding. It's a conundrum, I tell you.