Teleporting babies update:
So I had already reset the babies and that had not made the difference. I got the expansion and loaded it, uploaded my freebie content went back in and they teleported just as before, sim inside baby outside every time (that's weird). So I took twallans mods out and ran it mod free. Babies teleporting all over the place. Stupid magical babies.
So then I reinstalled twallans mods and boom, now they are sleeping peacefully and my poor incredibly tired parents are getting some rest. And there is an emergency baby retrieval door completely unguarded from burglars on the back of my house.
All is well-ish.