You working the mitts in the vid? Whoever it is, mitt man's got the best stance in the whole video. Maybe have them work foundation and balance. Those punches and upper body would both benefit a lot from better control and fluidity. They all seem to have quite a few pounds to lose, but let's assume that's why they're in the gym to begin with :good
You definitely look like the sharpest one in the video, only suggestion is let them come to the mitt, seems like you're meeting them half way
Most of the fighter's punching form look good. The heftier guy should take care not to stretch his arm out when blocking a right hand. But the mittwork looks good for what it's for, these drills serve the purpose of speed and reflexes, I can see why you say you mitt differently otherwise.
First off very nice and tidy stance I would only point out two things really but everyone above has mentioned already. The second would be to move the ring abit more i don't know if you do or don't because how short the clip was. You said it was only drills which of course is for speed,reflexes & in fighting approach but apart from that very nice pad work. Do you train boxers or just training people to keep fit ???
Nothing wrong with being a trainer mind doing all those pads drills - that must keep you fit to a degree.