Well, I'd prefer one of the girls to be the Furry...or both. They can also be partially furry/Catgirls.
Lol..A random Idea popped into my head...a Lesbian couple wants to have a child together, so they pay a guy to impregnate one of them...only they both fall in love with him too.
Or something like that....just randomly popped into my head. O_o