Congratulations! What a wonderful thing you are doing by keeping them together. I am sure the deaf one relies upon her sister quite a bit and seperating them would be very hard on both of them. I am sure you will have little trouble getting them adjusting. It will probably more of a struggle for you getting used to their behaviors, etc.
Lexus was adopted when she was almost two. Lexus was awfully stressed out for about the 3 or 4 days. She did some things that she would never do now. I wasn't hard on her though because I realized she had just been thrust into a situation with an individual she didn't know. The first night she slept on the couch by herself with her blanket that came with her and never moved until I went and woke her up. She looked so sad. The second day she tore up some cardboard when she was left alone. Just give them lots of love and attention to let them know that this is home and that they are welcome. Also, establish the rules from day one. They won't understand why they can no longer lay on the couch, when they could on the first day
As for the white - sunburn is an issue, although Lucy hasn't been burned yet. She does like to sunbathe though! I do use a sunscreen for kids too. Make sure you put it on good on the spots that the hair is thin, especially the ears. I usually rub it on her nose, ears, and back. The other advice I can give you is that Lucy's skin tends to be a little pink anyway, but it gets very pink around her eyes, nose, and lips when she is tired. So don't be alarmed if you see extra pink, just make them take a rest!
Good luck with your new girls! You are doing a wonderful thing!