Let's look at this......
Familiar with the voice (both girls)...
I believe they led a pretty sheltered life being that they were 9 and 14. They were active in their Ward functions (is that how to say it? ), and had a sizable family and extended family that they apparently were close to.
Functions they attended, because of their age were chaperoned by the parents, and Elizabeth did not date and was not interested in boys....
What voice, and person would that leave to be familiar with, so that if arroused in the night by this person, and talked to..she would quietly get up..get her shoes and leave?
What voice and person would be familiar with MK, so that she would not scream and wait 2-3 hours before saying anything to her parents? DID THE PERSON TELL HER THAT THE PARENTS SAID IT WAS OK ? (remember she is 9 )...
That's certainly a common ruse of people who abduct children.
I am positive that, in the interviews discussing Mary Katherine, either Ed or Lois has said that there was something besides just the sound of the voice--something in the context of what the person said--that tended to reveal his identity. The police have also very pointedly said that they are not revealing all the words that were said that night.
What voice and person would be familiar with MK, so that she would not scream and wait 2-3 hours before saying anything to her parents? DID THE PERSON TELL HER THAT THE PARENTS SAID IT WAS OK ? (remember she is 9 )...
Maybe someone trusted in the community? Maybe a bishop whom the girls thought should be beyond reproach? Maybe a distant family member? Maybe just someone who had agree to help Liz escape an intolerable situation?