Hi S.,
First, I'm sorry to hear about your mom's passing. You had me tearing up. =( I'm not looking forward to the day I lose my mom. That has to be hard not having her with you. Second, congrats on your new baby. Enjoy this time as much as you can. =)
About your daughter, I personally believe she may be seeing your kitty or mom or even someone else. A lot of people poo poo on thoughts of ghosts or spirits. Whatever! For those that do believe, it has been thotoughly reported that babies see spirits. For instance, my son (22 months), woke up crying in the middle of the night two weeks ago. I turned the light on very dim in our play room (once upon a time, it was my dining room). Jason was "talking" to someone. He kept pointing into the adjoining living room & saying, "hi". None of my cats were visible since they're dark grey & blend into the darkness easily. Anyway, Jason kept "talking". I asked him who he was talking to. It sounded like he said, "she doesn't speak good English". Mind you, Jason says words & his sentences are babble. My grandma was from Ukraine & had a thick accent. She passed away when I was pregnant with my first son in 2005, so she never got to see any of my kids.
Anyway, my thoery is that anything is posisble. They do say that our loved ones actully see everything we're doing (which creeps me out while doing certain things if you know what I mean). Obviously your daughter is way too young to answer you, but if it continues when she's older, ask her questions about what she is seeing. That would help her know it's a good thing & not scary.