Hi, NH Jumper!
I like the first photo quite a bit; it shows good, solid fundamentals - soft, relaxed back, eye up, correctly executed intermediate release with a nice loop the the rein. Because I also looked at the second photo, when I go back to the first, I see the seeds of the jumping ahead problem. You are a little farther out of the tack than is necessary for the horse's long, flat jumping effort. Not actually jumping ahead in this photo, but I would rather see you close your hip angle and be over the middle of your saddle.
I would also like to see you refine your leg position a little by moving the stirrup out to the ball of your foot and angling the stirrup on your foot slightly, outside branch touching the little toe. This is the perfect compromise to allow for depth in your hell while still being secure. This stirrup position is more of a xc, defensive position, which is fine ... for xc. However, you do need to learn to adjust your stirrup position and leg for different situations and different phases - for schooling in the ring and for stadium, learn to wear your stirrup in the classic position.
In the second photo, we see little position problems become big ones: your heel has come up and your leg has rotated back, and you've jumped *way* ahead - your crotch is actually in front of the pommel. It's a good thing your horse appears to be an honest guy, because a stop, or even a peck or a chip, might have you on the ground. What saves you is that flat, relaxed back, focused eye, and generous, kind release.
As for your horse, I love his attitude, but his form needs work. In the first photo, he's jumping very long and flat, and not making much of an effort to fold neatly in front or back. His forearm is horizontal, so I'd say he's safe here, but not tidy.
In the second photo, I am trying to make allowance for 1.) that the photo was snapped early in the jumping arc and 2. you've jumped up his neck, but even considering those two things, his front end is....not good, with forearms pointed down at the ground and legs folded under the body, rather than up. This is the kind of form than can result in the horse catching a knee and flipping over the fence. I don't think that's a real risk in this photo, as he's giving the fence a lot of air, and he's a good guy who's trying hard. However, when tired, put into a fence wrong or at a maximum height fence, it becomes a concern. Less obvious but more concerning is his hind end - he is pushing off unevenly behind, instead of engaging both hind legs evenly. I am guessing that sometimes he jumps to the right over his fences? And that the pushing off unevenly is more pronounced when he's not allowed to take the long spot I'm guessing he prefers?
The good news is that grid work and gymnastics will help him tremendously. He needs to learn to wear his fences from a shorter distance, engage his hind evenly, and use his shoulder to pick up his front end, rather than jumping in a bigger arc to clear the fence. More good news is that the grid work and gymnastics will give you a perfect opportunity to polish your position; working on keeping your lower leg solidly under you and closing your hip angle and staying over the middle.
Overall, you're an athletic, sympathic rider with the potential to do more. Good luck to you!