Thanks for liking my work! And I do have a ton of these already planned out.
1) I have route specific antagonists like Pierre and few others, but I also have a few general antagonists that'll appear in all routes.
2) I'm planning for most of the routes to be slow burn. Ya know, almost touches, little glances, that kind of stuff. Especially since it fits in with Felix's backstory. (Also I love slow burn and torturing people with it lol) Also, if there were going to be any nsfw it'd be like a major reward at the ending. But don't count on it, I'm still only considering it.
3) Close proximity (Especially the Aka scenario you describe) is a must and have already been planned for all love interests. Although I discourage the use of AI art to make your point, it harms artists. I already understood you from the definition alone.
And again, thanks for reading! I'm in my finals week at the moment but will resume development right after my final paper.