Characters with vaginal sex scenes for Krowly;
Goblins, Orcs IIRC, Busty Elves, Snake Girls, Plant Girl, Rose, Alice, Melissa, Carla, Fina, Agnieska, Mabel (not sure, please someone check if they can). That's all the ones I can recall offhand, but as you can see it's not as little as you're making out.
For Eric;
Jenna.
Sort of.
It probably has greater meaning/import than anal does (can't recall if it's stated as such either way), but it's also a definite taboo when it involves family members as explained by Sister Elizabeth whenever she tasks Krowly with fucking Jenna's ass.