So, let me get this straight . . . You and your daughter both dreamed about Julia and Helena, on the same night, and you had never mentioned these dream people to each other before? If this is the case, then in my opinion, you were not really dreaming at that point. You were in the in-between place, Bardo, making plans.
Your physical selves were, of course, sleeping and dreaming the whole time. But, let's leave you there for a second.
In Bardo the communication is instantaneous. You speak heart-to-heart. Your daughter "got there" first. Please remember, this is a state, not a place. Then you arrived, probably with a guide or two (and Peter's?) and then, Oh Joy!, Julia showed up too!
You told the universe, "Who better to get them and bring them back, than Peter?" Such things, spoken from the heart, especially in Bardo, become a promise written in stone. Peter, when things fall into place, will gather them to you. It might be in this life, it might be the next, or the one after that. But, it WILL happen. In my opinion, you just made it so.
My interpretation is this: I think Julia, wherever she is, un-incarnated or living happily in the Midwest, just received her "announcing dream." Helena or Peter is about to be born. Peter will be the hub or the wheel that connects you all together.
Now, let's return to your sleeping selves. Your sleeping minds will incorporate these feelings, passed between souls in an instant, and it will show up in the Dreamscape. So, that said, is it any wonder that this conversation happened, in your mother's house? Or rather, The Mother's House? Or that it was a family gathering?
Your daughter wants to tidy up some unfinished business.
You saw the girls the way you remember them. In this way, the dreams may be past life related.
Peter was wearing the torc. He may have actually had one, back then, but you noted it in particular, so it is important. He is the King, the main actor in this scenario. He is the circle, the wheel, around which you all turn. He will, of course, have to accept this charge (the torc, again. A king / slave vocation), but "they" have a way in Bardo of getting you to accept.
Trips to Bardo, by the way, also leave me feeling unsettled. What is said there happens so fast, and is of monumental importance.