Make sure you just stand there for a second after you complete the lift. Every time. You don’t want to be in the habit of re-racking immediately upon completion.
Depth - yours was fine, his was borderline.
Locking the knees - you both were pretty wiggly here, tbh. I unrack, walk it out, then make a visible effort to lock my knees and not move after this. I make eye contact with the head ref to let him know that I’m ready and locked. In USAPL, the side judges tell the head judge when your knee is locked and you are ready to go. If one doesn’t think your knee is locked, he won’t tell the head judge to let you go and you’ll stand there sapping strength.
Also, if a side judge says you’re ready, puts his arm down, and then you pop and relock your knee before descending, he can flag you because your initial pop-relock was the “squat”. I’ve never seen it done but I was warned about it in my second meet.