I agree with you on the last two points (I don't have glasses on at the moment and can't see your hands too well)
With your legs notice how they keep coming in and out, in and out like your leg is locking and bumping against his side. Is this intentional or not? If its intentional you need to work on asking and following through instead of nagging after him which will eventually "dull" him to your cues (trust me I've worked through this). If its not intentional focus on flexing at your ankles up/down instead of in/out where when you come out of the saddle your heels drop ever so slightly down and when you come down your heels will feel like they are coming up even more slightly but really remaining neutral. This will also help lengthen that leg.
If your 3rd point is saying what I think its saying: you hit the nail on the head.
Other than that, in your posting you look like you're doing an awful lot of work to push yourself out of the saddle so it ends up looking something like: up....down. up....down. up....down (or that you are focusing and therefore taking too much time to rise out of your saddle) Try thinking either "up, down, up, down, up, down" or "down, down, down"
Being really picky, at the 4:10 mark when you ask for a halt you ever so slightly pull yourself up through the reins rather than sit down on your pockets to halt. Think "sit down, rock your shoulders back, and then bend through your elbows to take away the slack" rather than to pull your horse back. Have you ever tried halting without reins?
Your riding looks super good though and take everything I say with a grain of salt, after all I think I just did the whole ~melancholy post in the Horse Talk section~ thing. Best of luck!
"I don't think he ever gave a thought to other people's opinions, which was just as well because they were often unkind."
-- James Herriot, All Creatures Great and Small