All 4 of my family's Imaginary Friends just got tossed back into the child's inventory. Good grief! The kids were hungry, exhausted, and smelly. I got them fed and ready for bed, but the IFs kept interfering with the sleep command. I'd send a kid to bed (with a completely red energy bar) and the IF would come start talking to him. Over and over. It was after 2:00 a.m. before those kids got to bed and they had school the next morning. They got so tired they were passing out on the floor. As soon as I finally got them to sleep and the IFs turned back into dolls, they went into inventory and that's where they'll stay!
I've been lucky with my IFs, none have been that bad! }:P
I did have a set of natural identical twin girls get IDENTICAL IF dolls. They were both singing to them at the same time, and it was downright creepy.}:P
My first IF that I turned into a real Sim, married into the family. (they're the couple that had the natural twins). Their oldest, a boy, is absolutely adorable as a toddler. I'm hoping the girls are too and that it continues through the ages.
The boy got a doll within hours of being born, in the mail. The twins got theirs the next day. They all do have the Loner trait, so that may have something to do with whether all kids get a doll or if only select kids do. I'll have to test that out when my current family's first child is born in a few game days.