If your vacation is planned for soon, I doubt your puppy will come into heat by then since you say that's when she'll be spayed. Once spayed, she will no longer go into heat.
If you are scheduling her spay for when she's about 5-6 months, chances are, you will be in the clear. We can always pray.
Snoring is not always a good thing because of the reason/cause behind it. But snoring babies sure are cuties! My late shihtzu snored, and so did our family Tibetan Spaniel. I would have to say, my shihtzu was the loudest of the two. It was comforting to hear her snore and I would fall asleep to that like listening to a lullaby.
And yes, that is a good indicator that they are indeed getting their rest and are alive and well.
Congratulations to you on your pending new arrival. These little ones are definitely more like children than the dogs I've raised before.