Zorlun, thinking about the Katherine aspect...
What about something like Katherine finding some video of Myriam doing the various kind of stuff (of course, to be seen in what way and situation Myriam would end up making a video), and then getting inspired to copy her and try herself ?
I know it woud move away from trying to have all the sex scenes involving only Myriam, and would take out the possibiity of using the direct interaction Myriam-Katherine to see the reaction (thus change the stats, and the evolution) for Myriam.
But if the thing was Katherine knowing/finding out what Myriam tries/does, then trying herself (or not, that can give the player a possibility of also influencing the evolution of Katherine), and then Myriam knowing/discovering what Katherine is experimenting (and the player having the possibility of deciding how she feels/react), that could give the possibility of still keeping the possibility of the two characters somehow influencing and guiding each other, even without any direct sexual connection.
A link, instead of the video, could be Jennifer.
You cannot show Jennifer, Myriam and Katherine in the same sex scene, because you have been forbidden to have Myriam and Katherine in any kind of sexual situation.
But you can have Myriam showing/teaching Jennifer (who is anyway a bit more "free/daring" type), then separately Jennifer doing the same with Katherine.
It would require changing a bit, and I guess expanding, how you had expected to use Jennifer, but then again, you had anyway to change the game due to Patreon, effectively cutting out stuff, at least this would not be a cut.
And could give you extra decision points for Myriam's evolution: does she involve Jennifer in, or anyway show her, any given kink and in whatever given situation she has the opportunity to, or not, and how does she react then if Jennifer does it, or not (if you leave a choice on that) ? And when she finds out Jennifer spoke about/showed to/involved Katherine, and Katherine eventually (if the choice is left to the player) does it, how does Myriam feel about it/react to that ?
If Patreon has closed you the door, you can still go through the window, you will not be able to carry with you through it with the furniture (the Marc stuff), but you can find ways to at least carry with you some pictures (this kind of stuff, or something like that you come up with) ;-)