I hope you don't take this as being too critical, what you're doing by teaching ccw is very good thing.
A few thing which can't be seen in the video; pistol presentation from the holster, foot movement while moving.
Correct presentation from the holster is important, how a two handed grip is applied in the draw stroke also matters.
A one handed pistol grip when you add in a shitload of adrenalin in a real shooting situation is not the most stable shooting grip imo.
Movement laterally without correct foot movement is a good way to end up on your ass with a pistol pointing where?
A blank sheet of cardboard is not helping in keeping shots in a specific area, without a point of aim is a good way for a shot to go errant which in a real world scenario can lead to collateral damage.
I'm not a big fan of not using sights, at 4 yards that's not an issue, but the idea is to train one method for all distances, since sights are needed at longer distance is why sights are always used, to change shooting technique based on distance is problematic.
I realize your class is a one day ccw, and I'm guilty of inserting things which are a result of more extensive training.