GiGi and Poppi

Gigi and Poppi came to visit yesterday and spent the night so they could watch the girls today. They offered to sleep in our room with Gracie so we could get a good nights sleep. We worked hard to give her a pretty good bedtime ritual...eat, play, bath, fall asleep on Poppi. I thought she might wake again at 10pm to nurse but she didn't and I was sleepy. I figured they had a long night ahead of them. The night before she woke up every 2 hours!! Well...she slept till 4 a.m. for Gigi and Poppi!! That is 8.5 hours between feedings. What's the deal???
Now they think we are being a bit overdramatic about our lack of sleep. :-) THEY SAID SHE ATE AN OUNCE AND FELL BACK TO SLEEP! I was up longer than her in the middle of the night to pump. I am hoping tonight is similar.
Sydney loves her Poppi more than anything in the world. She was kind enough to share him with Gracie this weekend. I think that Gracie is favoring Gigi at this point. She gave her the biggest smiles and would quiet down as soon as mom picked her up.
We have scheduled portrait sessions for Thursday morning. I really wish I had some taken when she was a newborn. This will just have to do. I was running on empty when she was a newborn.
I have been trying to decide if I think it is ok to let her cry herself to sleep. I am starting to think that it is. I have been rocking her for 20 minutes tonight and she just kept sucking on my shoulder and whimpering. So I decided to put her in the bassionette to see what will happen. She cried a bit but was asleep in less than 5 minutes. Do you think self-soothing is the right way to go? Will it make her a better sleeper in the long run?