I've heard the voice. I shit you not, I heard it with my own ears.
Kyra went down for bed at 7. Jer went to clean the bathroom at 7:20. At 7:40 I heard what I thought to be Kyra mumbling something unintelligible. I have no idea what was said, or to who, but it was a girl mumbling. It struck me as odd because I hadn't heard Kyra yapping to her dolls tonight. Jer came into the living room a few minutes later and made a comment about how it didn't take long for Kyra to go down. Confused, I said "She's asleep?" he said she was asleep before he started on the bathroom.
Maybe my MIL isn't quite as crazy as I thought.