Most girls are optional. Apart from Lisa, Layla, and to some extent Astra, you can choose who to have NSFW interactions with.
But when it comes to taming, since it's such a big part of the story/world, that's not something I'd prefer to have optional in the same way. (Example: Aurora's taming with a Kiss)
Pregnancy is also on the way, I'm just getting all the plot points ready for it(It will be optional though).