Linz,
I think you are over thinking it, or thinking way too far ahead. I think Layla will do no better any where else than with you. I think you will get the hang of taking care of her. You will do what needs to be done and you will give her the love, warmth and healing strength of your presence. I know this is so scary and stressful and emotionally draining when you look at the BIG picture. Try by looking at the small pictures, her coming home and how you will care for her. (thats it. not the future care, just the NOW care.) Then, her recovering from the surgery... no matter what may or may not happen in the future, right now she has to recover from the trauma to her little body from the surgery only. Don't think about whether she will walk or potty again, right now. Just think about how she will need a week or two to recover from the invasion to her little body. She needs you and you are doing an AWESOME job taking care of her. You CAN bring her home and YOU CAN care for her the BEST.
AFTER all that is behind you, then get through each physical therapy session. KNOW that right now she's not going to JUMP up and RUN to you. But don't think that she might never. Just think, right now. Its so much less overwhelming to your emotions to deal with the here and now, you can't predict the future. Miss Layla is sooooooo lucky to have you as her mommy. Keep her safe, warm and close to you. Pray for her and keep working with her. Miracles happen, but as you have read, they usually come with love, dedication and work. I have so much faith in you and your abilities.