First: can you get the characters pregnant? Second: is there potential for twins or higher? Three: can you increase that potential? Four: is there an overlay or dirty talk that discusses pregnancy?
Yes, anyone in the mansion, including the player, can get pregnant.
Not without mods. AricsExpansion allows for twins and triplets.
No, for AricsExpansion you can adjust the setting using the Constants mod.
Without mods there is minimal interactivity with the pregnancy. There are text indicators of the pregnancy and you can choose to abort the baby through the slave guild or by potion. AricsExpansion includes pregnancy in the slave tab's talk menu, though the effects are somewhat limited.
