is this video representative of good technique for working with gas pipe
Ok I watched the video, union's usually have a valve in front of them.  I am not sure what that gained other than showing the proper way to support the pipe (2 wrenches) to prevent the one side from unscrewing, did he over tighten it looked fine to me, as far as the dope he used I could not see if that was gas rated.
Can you use two much dope? Not really it is just a waste of $ and did you notice he wiped off most of the excess. I will also put my shutoff valve before the drip leg , the pipe hanging down and capped close to the point of use.
The drip leg is There to catch debris and moisture that is a really short one but some places don’t have lots of issues.  Being able to shut off the gas and clean the drip leg was a big deal at my last home we had a high moisture content due to our location on the line.
That video looked appropriate to me other than the union not having a shutoff and the same with the drip leg.