1. I don't believe this should be possible. If you have no penis, scenes with it will use strap-on, but impregnation shouldn't apply. Perhaps you got them pregnant some other way.
2. This is to prevent action abuse for mana mostly
3. Child's grade is inherited from mother. MC's original grade is slave (I've planned to increase it with progress, but forgot to add it).
Glad you enjoy the game :)