Those are very similar to the techniques that we taught for scuba rescues as well. Biggest difference being when you come up behind them, grab their 1st stage valve at the top of the tank, pull them up and back and lock their tank between your legs, reach around and inflate their BCD and pulled them in holding the tank valve.

It's a little easier, if done right, with that tank and BCD between you. They have a much more difficult time reaching around and grabbing you.