Ahh, okay!
Feel free to consider that a suggestion in case you want to include it (though I bet it would take a bit of work to include a pregnant version of every art asset, so I bet it won't be easy)
Yeeh, that makes sense!
I do have one alternative suggestion, in case that would be easier; If the succubus herself can't get pregnant, perhaps you can include pregnant NPC characters? Needing only images for that specific character should make it much easier, unless I'm misunderstanding how it works
Either way, no stress!