Hey Liz,
I think you're off to a great start! Your videos look great and the ratio should work.
Only thing I would do is spread the rocks out a bit so throughout the tank to give different fish their own territories. When they get bigger and more assertive, I wouldn't be surprised if it ended up with one fish taking over that whole cluster and all the others at the other end or in the top corners of the tank. Kenyi get big and angry.