About your sims' confusion:
My sims get question marks over their heads when one is trying to interact with a baby but another sim has already queued up an interaction with the baby.
Like, the baby cries, one of the children on the opposite end of the house throws a whim to interact with the baby, which prevents the parent from actually feeding the baby or changing the baby's diaper.
On the other hand, if you simply want to be rid of the baby, can't you go to the CAS screen then click on the baby at the lower left of the screen to delete it?
(Or did you have to go to Manage Worlds/Household Management/CAS?)