Christian and Tara are the only other characters in the right age range (I'm assuming Amanda would have recognized if she were the one herself), but neither seems likely. I'm pretty sure it will wind up being Jaye.
As for how we get around Patreon... well, it may take a while to confirm Amanda's suspicions, giving us lots of time for navel gazing about how unlucky it is that their love must be so shockingly illicit. Then we'll finally learn the egg wasn't actually substituted and thus boning Jaye was absolutely not incest all along.
Absolutely not. Stay strong, Mal!!