I'm gonna throw in my guess for the blackmailer: it's Moira and Jessica or just one of the two, most likely just Moira.
They found out about Ashe and know so much about what's happening at Vanessa's house cause there are hidden cameras put there by Moira to keep an eye on Vanessa.
Ashe in episode 2 masturbates in the bathroom at Vanessa's place by taking off her shorts and panties and was recorded. At the dinner Moira shows interest in Ashe and offers her the mascot role for her campaign because she know's Ashe's a duplo, and I also think Moira wants Vanessa to get with a duplo to be a mascot and show Moira as socially progressive and that's why Vanessa needed a fake girlfriend for the dinner. This would also explain the freak out at the end of the party in ep 6.
I think Moira is doing all this to have enough material to force Ashe and Vanessa to accept the role in her campaign and because she enjoys having control over Ashe.
