I actually wonder if we are getting a Cynthia path too or if she is already a couple with the other unknown serpent.
I'm kinda doubting we'll get a Cynthia path (though I do have a feeling we may get some naughty pics for MC's "Wet Dreams" section & also some original renders in the gallery [non-in game images]).
If she has feelings for one of the other Serpents, I think it might be for "Serpent" (the sniper, aka "Mr High-Five-Guy by Gottardo).
I think Gottardo mentions in the beach prison event that only Wilfred & Cynthia knows his real name (though I think that isn't quite accurate, if theory about "Serpent" being Rina (MC's mom)'s ex-fiance ends up being true, then the more accurate list of people who know his name would be Cordia, Wilfred, Cynthia).
Wilfred probably knows since Cordia is his protégé (thus he would most likely know a lot of her past, including "Serpent"'s name), but with Cynthia, I think she knows because she might have quite close personal relationship with "Serpent."
Though it might be more of an unrequisited love from her end. with "Serpent" likely being Rina's ex-fiance and still caring deeply about Rina.
Hopes also mentioned that one word to describe the last hidden Serpent's personality would be "evil." I could be very much wrong, but not sure that sort of personality is something Cynthia would be attracted to.