I only see the following:
1. Reused the drain plug crush washer (do these have crush washers?) Unless I missed something, it appears as if he picked the drain plug up out of the drain pan and screwed it right back on.
2. Applied more torque than necessary on the drain plug while restoring.
3. Didn't lube the new gasket; however, he didn't wipe the seating surface down, so residual oil might do the trick.
4. Overtightened the oil filter canister.
5. Spraying anything from beneath the car. Even if it's not detrimental to gaskets, the simple fact that he's spraying from beneath is cause for concern. He may be cleaning most of it, but he's displacing the rest - to the belts, other parts of the engine bay, etc.
Dropping the splashguard - who cares! Worrying about scrapes or nicks on an splash guard is silly.
Did I miss in the video where it showed he was using carb cleaner?
While I wouldn't bang the side of the filter canister, the chances of what he did damaging the canister are slim. What he could have done to preclude having to bang it, is wear some darned gloves.