Thank you for your post!
I think my vision of what I want combat to be is around the halfway point of what it currently is and what you are describing. I do plan on including in-combat interactions within the party, but more so in the form of supporting abilities rather than in-combat dating. What you are describing using the term "fertility" technically already is in the game, but unused until I have drawn the needed visual assets and such, it is an invisible counter that will trigger events and unlock dialogue options for example.
For now post-combat scenes are not yet in the game and just are WIP placeholder dialogue, but I don't intend to gatekeep all the post combat sex scenes and events behind the "game-over section". What you get will be how you played. Did Taya ride all targets into submission and won the encounter? Well, then there is going to be a victory scene featuring that, so winning will also reward you, just the context is going to be different.
Your last paragraph reads like it'd be more suited for dialogue events rather than combat encounters, a sort of bartering with gathered knowledge about the subject's likes/dislikes, appeasing their preferences to reach a goal that may or may not come with unintended benefits/consequence. I will most likely include something like this in dialogue events, because it does sound fun.
Feel free to join my discord, once I have fleshed out the combat a lot more I'd like your opinion on it again.