I'm going to give you a big
here. I sincerely hope that you will decide to keep Skye. She is beautiful and I think she will get along just find with your yorkies if you teach her properly. Get a trainer right now, and just work with her. Work with her as she gets older, and she can and will learn to be calmer around the yorkies, and she'll eventually understand that they are smaller than her and she needs to be careful with them.
I canNOT stand it when people judge this beautiful, loving, GENTLE breed based on their bad rap (which is way out of control, btw). Pit bulls are one of the most loving dog breeds in the world, and I wish I could have one. One thing I'll tell you is to NEVER be nervous when they're together. You should be keeping a close eye on them, but do not get stressed out. They will sense it, and they'll get stressed out, which won't equal a good thing. if you ever feel tensity between them, get her OUT of there, and seperate them. But try to be calm when you're doing it.
Patience, love, and proper training and your furkids will have a wonderful playmate, and your son will have a loving companion.
Best of luck to you!