I made Oriana fall to me by using her sister (with had her relationship bar completely high). It was easy at that point and it went to weird places after you have both girls maxed. I hope the dev makes a new update and add more girls or a new town.
Found out Mirel is in fact a hermaphrodite, who has hopelessly high libido. In case that changes things for you. Personally, I don't remember if she ever brought it up as I'm 40 days in to my main one save files. If it ever did, she never brought it up again, and it surprisingly never came up during intimate times, thought the libido thing was kind of starting to be a thing I was aware of, not not at hopeless levels.