The first mare is the nicest of the three by far, but I still wouldn't take her if it were my money. Her hind legs have really abrupt action, and the soreness problems would worry me. However, if you really like her and she vets sound, I think she could be a great little mare for pleasure and low level jumping.
I would pass on both horses you just posted. The first mare has very choppy trot and sub-par movement, and the second horse's conformation doesn't impress me. I wasn't able to watch the video of the second, but of these two, she's my favorite.
That being said, I think if you keep searching you can find a lovely OTTB with good conformation, sans soundness issues. They're a dime a dozen right now--you just have to know where to look.