Good stuff. I taught kids how to swim and coached swim teams for years so I can see how frog kick would be the easiest to teach. But, if you have time in A-pool to have time in the pool I'd strongly recommend folks to try and learn the eggbeater. It certainly isn't easy to learn and it isn't easy to teach but it's the most energy efficient form of treading water especially when coupled with effective and coordinated sculling (use of hands). I'm fairly positive I could tread water using the eggbeater method for hours even today. I'm not sure I could scissor kick for more than a minute or so and would be completely exhausted after those minutes. The other important part to recommend of treading water is body position; if you're essentially sitting in the water then you'll barely have to move your arms and legs to keep your mouth out of the water. Also, the goal is to keep your head up, not your chest or belly. You're survival swimming, not playing water polo.Check out chapter seven for information regarding the treading portion. It seems like different kicks are okay but aren't taught because of difficulty to master. I was taught the modified frogkick and it works for me. But then others do the eggbeater and it works just fine, too. I have yet to see someone successfully do the scissor kick. Usually it drags them down when they have boots on, but hey, it might work for you.
https://www.public.navy.mil/netc/centers/cnatt/nascweb/model_manager/files/swim/netc_1552/netc1552 16.pdf
That said, if you're not a good swimmer go to the open pool sessions and get help from the instructors. Then go spend a lot of time in the water. Go play in the deep end of the pool with your buds. Find some sort of hidden swimming to keep practicing. Probably not as applicable to the average SNA but I spend a lot of time treading water when I go play in the pool with my kids especially if I'm staying close at hand while the youngest goes off the diving board. Something like that is all good practice.