"If you pick one is the other one off the table for life? Does the game assume you never want that other one?"
It depends. Sometimes yes, sometimes no. The trouble is, some future scenes only make sense if the previous one happened. So, with each kink choice the player may be directed to a given path. Although, I also try to not make this a hard rule so that rejecting a kink you don't like doesn't necessarily exclude you from a girl's path.
This can be tricky sometimes because if a scene (for example Deb's feet scene on chapter 3) is rejected, now I have to write the following scene in chapter 4 differently to take into account whether the scene on chapter 3 happened or not. As you can imagine this can get very complicated quickly.
That being said, I agree that rejecting Deb's feet scene on chapter 3 shouldn't lock you out of her path. That was an oversight on my side, sorry about that. I'll rewrite some scenes a bit differently to allow her lewd scene on chapter 4 to still happen, even if reject her lewd scene on chapter 3. The next patch I make will have this fix. thanks for pointing it out.
As for Emma's kinks, yes each girl has her own kinks and some might be less vanilla than others. I'm aware that, the less vanilla the girls are, the less some players might like them. But I'm okay with that. The goal is that each girl feels like a different person with their own needs and kinks. As long as each player finds at least one girl they like, it's okay if they don't like them all.