I'm totally going to rip your form to pieces. I kinda feel sorry for doing so. I suspect several of the technique issues I've spotted are the effect of the fat gripz, either causing weakened grip to inhibit technique directly or causing reduced confidence in grip to inhibit technique, and your final set of pull ups adds weight to this hypothesis. The resolution of course is not to remove the fat gripz but to just be all the more conscious of technique while they're there (or, perhaps, to conclude that my judgements are wrong).
Hmm, looks like your knees cave in a little at the bottom of the deadlifts. I'd try straightening up your feet so that they're parallel, and if your knees still dip in at the bottom, then move your feet in closer. Looks like you're keeping the bar out away from your legs, and you might be in a more mechanically advantageous lifting position with a little more knee bend at the bottom. Of course, then the question is are you deadlifting to move the most amount of weight (longterm, obviously the presence of fat gripz means you aren't trying to lift the most weight possible within the session), or for a different adaptive goal? The distance between you and the bar, and the appearance that a little more knee bend would help, makes it move towards stiff-legged deadlifts. Not a technique problem, but I noticed you always go right over/left under with your mixed grip. Do you notice any back or bicep imbalances developing that way? Last thing I noticed with your deadlifts is that as it gets harder, you've got the temptation to get the bar off the ground with your arms rather than your legs and hips. Again, bar to shins and more knee bend at the start would probably facilitate resistance to this temptation, and I definitely think that the fat gripz promote this temptation. As I said above, solution is not to remove fatties.
On the 1-arm DLs, it might just be the camera angle playing tricks on me, but it sometimes looks like you'r getting more hip extension at the top when using your left arm than your right arm. When I first read that you were doing 1-arm DLs, I assumed that you were doing it suitcase style, ie leg-leg-farmer rather than leg-farmer-leg. I don't think one is more right than the other. Doing it the way you're doing it will probably allow much more weight to be lifted than the way I initially imagined it. Your starting position looks far more advantageous to me than with the barbell DLs. The one thing I'd be most concerned about from a safety standpoint is the rotation through your trunk as you do these. Being a one-armed movement, it's not in the least bit surprising that there would be trunk rotation, as 80kg+ hanging from one side of the body will do that, but torsion + weight is not exactly friendly to a spinal column, and especially knowing that you've injured your back this year raises some worries.
I enjoyed your flailing about with the pull ups. Grip was a very visible struggle there, and you can see the difference on the reps where there are no grips. I notice that at the top (when you make it that far), you tend to round your chest/upper back, which is a sign that you may be deferring away from your scapular retractors and over to your chest to get the full distance. I'd like to see more thoracic extension at the top. What do you tend to be thinking when doing pull ups? I've noticed that prettier, back-oriented technique often comes more reliably when people are focused on keeping their chest up and tucking their elbows down rather than thinking about pulling themselves up.
