Well, I can see that your horse is kind of bouncing around from contact with your hand, to not contact, from giving to the bit to coming above it, to bracing against it, to hesitantly reaching for it. It must be very hard for both of you to find , and keep, that 'sweet spot', where he is connected to your contact and moving forward.
I think that since there is so much going on with the contact that the hrose is losing his impulsion, which is then making it harder for you to post on him, which then makes you more reliant on your hand and less able to have your hand and seat be independent from each other (which is absolutely essential for the hrose to trust you and come onto a steady contact.)
So, first of all, I'd work more on just having him go forward and worry a lot less about the contact. See if you can get him to trot forward , let him have so much rein that it's just looping , but give it to him slowly and see if he wont "take the rein forward" as you give him more. And, when you give him more rein, ask him to move into it, to move forward. when he does, you let him go forward, and concentrate on just posting lightly on his back.
Then, start to pick up the contact, slowly and in rythm with his trot, until he flexes a tiny bit. relase and ask him to stretch down and forward - all at the trot. so you kind of have him stretching out, coming back a little, stretching out, coming back. as you go along, you can make the "coming back" part a bit stronger, requiring him to be on the bit for several strides before you go back to the stretch and come back again.
He's a very nice looking horse, and your EQ isn't so bad. I dont' have any advice on the leg. It'll get better in time. you are young and your body will recover fully, i would guess.