SQ: Knees are about right. Just try and bend your hips and knees simultaneously at the start and lock your knees into position by about halfway down, then reach back with your butt. Depth is borderline. A slightly wider stance might help.
PR: Your wrists are bent back a bit too much. Point your middle knuckles up. You also could get tighter in the start - bear down with your abs when you take your breath (a belt will help). You are also initiating with elbows flaring out right away. Try and have the first part of the press keep the elbows in a bit more. This latter part might be causing the irritation.
DL: Start with your hips a touch higher, so the bar is back more over mid foot. You are setting your back right, but you are using your head/neck (craning up) in the process. Try and keep your neck neutral with eyes focused on the floor the entire duration of the reps. You can bring the bar down as fast as you want as long as you have control and keep your back tight. Just don't put it down so fast that you completely lose your setup position and need to spend excesses time between reps readjusting.