About Yoga, I really don't know the answers to your questions. I have heard of many people resolve issues with a crooked spine with it, but don't know much more than that. You have to do your own research. I would recommend finding a Yoga expert in your area and talking to them personally, as this is a very delicate matter (the spine is crucial for health as a whole) and any experimenting on your own, even on the basis of good sources (books, sites, etc.) is likely to cause harm. Or you can seek online experts, forums, sites, but the best thing is personal contact, I would think. Someone who knows about this stuff has to inspect your daughter and decide what's good for her. Look for Yoga classes, they are practically everywhere in the big cities.

About UT, I doubt that external application of urine will have an effect on the spine (in the mechanical sense of "straightening" it up), but it may have other beneficial effects. In a desperate situation one should try anything, imho.
Give her as much of her midstream urine to drink as she can take without unpleasant symptoms, this should keep her health stable, as it would counteract the inevitable harm from scoliosis.

Good luck and take care!

P.S.
If you Google "yoga scoliosis", a lot of stuff comes up
http://tinyurl.com/crygnc

For example:
http://tinyurl.com/c4oezj

http://www.yogaforscoliosis.com/

http://www.yogajournal.com/practice/1060

http://www.scoliosis.org/store/yogafaq.php