WOW! You have improved so much! Here are some things that you still need to work on:
Getting your heels down. That will also come easier if you shorten your stirrups a hole or two. Put your weight onto your heel and really stretch down with them.
You have a slight chair seat, pull your lower leg back and hold it there. It will be painful at first, but after a few rides it will stop hurting.
LOOK UP! If you look down that's where your going to end up, I've learned that one the hard way, it's not fun. Haha.
You look a little tense, make sure your taking deep breaths and your relaxed. Your pretty pony (horse) will feed off of that and will start to listen to you more (not saying he isn't now).
Now that I look at the canter pictures, you really do need to shorten your stirrups. Bring them up two or three holes.
When you half seat the canter you don't need to come out of the saddle so far (I used to do it JUST like you are, which is OK). Don't worry about that one really, it's just helpful if your horse spooks, it can keep you from falling if you stay close.
I really like your jumping position and his too. Just a few touch ups and you guys could be doing hunters and placing well! :)
Again, push your heels down. I like that in the first jumping picture they are somewhat down, that has to be my favorite picture out of all of them. Shorten your stirrups a few holes.
You leg is swing back a bit. Try some two point work at the trot and canter and some no-stirrup work too. That will build your muscle up really fast. That will also keep you from over jumping.
I love, love, love your release. It's big, but that's good for an OTTB learning to jump.
And great job looking up and ahead! That's what I love to see in a rider :)
Overall you look good. Just a few things to touch up and you'll be a hunter.
Sorry for tearing apart your riding, just want to make sure I got everything. I love your horse by the way, super sute!