[ctchocula]

My understanding the same as that of my two sibling comments. You just need to demonstrate excellence in your field in order to get an O-1. For example in Computer Science, that might be X citations in published work, Y reviews you've written as reviewer (counts as service), and letters of support from experts in the subfield of Computer Science. If your pianist friend has won international competitions, CD recordings and performed with orchestras around the world, that surely counts as excellence in her field. She should consult an immigration attorney ASAP. Even if initial consultation costs money (and it often doesn't), it sounds like a worthwhile path forward if she wants to stay. O-1 is not as prestigious or rare as you make it seem.