I can't really criticize the Arab.
The little palomino in the first and third pic is hanging the left knee pretty badly. In the second pic the knees are adequate and even; but very loose below the knee - looks like it was a long spot and he's "reaching" for the fence.
I would stick with this size fence, and do some grids or gymnastics work to sharpen up his front end. Overall,he looks pleasant and willing, making a nice effort over the fence and jumping round, but seems to be somewhat limited.
As for the rider in these pics, first pic -
Lower leg good, eyes up and looking toward next fence, good, release ok - hands could be a little further forward. Base too far out of the saddle, and knee angle too open, upper body laying on the neck. Allowing the hand and arm to release rather than using your whole upper body.
Second pic - equititation looks quite good here, but angle of the pic and watermark make it hard to be precise. Need to be looking up and focusing ahead.
Third pic - pinching and rotating on knee, lower leg loose, jumping ahead, looking down. Release good.
Turnout of horse and rider is excellent in all three. Curious as to what type of show, and why the long natural mane and no braiding?