In all of those photos you appear to be rolled forward onto your peepee, or, your "fork", for a more appropriate word. In hunt seat riding, you may have your legs shorter than in western, but you still should not be riding with so much contact on the front part of your pelvis. You appear to be rolled forward, and then with heavy knee contact, too. if you ride this way toward a jump, and the hrose props (stops suddenly), you will be projected right over his head.
I realize, you aren't going to be jumping any time soon, but you asked what about your seat is not "right".
Also, in English, you will have a bend in your knee, but your weight does not stop at a gripping knee, it goes down into and through your ankle, as your foot rests on the stirrup bar. you have a "clining" type seat there.
in any case, take some lessons and then post how it's going for critique, ok?