If you line the point of the hock up directly under the point of the butt, which is the case in the 3rd picture on the top row, you see that the lower leg is angled under the horse. That is sickle-hocked.
But in the 4th and 5th pictures, she looks perfectly camped out - not a lot, but some. The cannon bone is vertical, but the point of the hock is behind her. So, I think until we see a true comformation picture (all of these appear to be at some small angle, which is more likely making her look s-hocked in the 3rd picture when 4&5 are a better representation) it's a bit of a guess. I'm leaning towards camped out though. Not bad, just a little. Even if she's s-hocked, that isn't bad either.
As a rule, sickle-hocking will result in more extravagant movement in the front legs, and there will be greater engagement of the hock joint.
The little lunging you are doing should not be a problem.
If the mare is sensitive in the loin area, I would either suspect the saddle or the way you are sitting it.
A saddle whose tree is too narrow for the horse on which it is being used is one of the biggest offenders for creating loin area pressure points.