Having coached a lot of basketball for my 4 kids as they passed from ages 5 to 15, I'd say you have the gist of it. Keep everyone busy and split them up to get more "ball time" whenever possible. And lean on your assistant for most coaching of your own kid - it always worked better for me and my assistants. And I LOVE to "play in" on scrimmages because it gives you a chance to put a little bit of a cap on the best kid so he can't just dominate, while allowing you to reward someone who sets a screen or even set a screen and call for your teammate to use it. I teach a pick drill early in the season so the kids understand which side to come from and I make the ball handler come close to the screen to force their defender into it (something it seems Shaka has not thought of). I start as the defender so the screener needs to impede my defense and the ball handler has to properly use the screen. Then I build into a kid as defender and teach pick and roll with me as second defender so that ball handler has to decide to take to basket if screen works or pass to screener if I switch.
And, at this age, when you really need a basket, you have got to run the "star play". Inbounding from under your own basket, the 4 kids spread to the 4points of the star (outside the 3 point line) and they will be followed by their defenders. You choose either the best mismatch, or the best kid, or the kid who has never scored, and they run to the basket, leaving their man behind. It seems ridiculous, but the rules probably make the savvy kid from the other team not be allowed to lie in wait under the bucket, and I cannot tell you how often it has worked - even multiple times in the same game. If you keep coaching next year, you might add one screen for the kid to run around, but for 1st and second graders it's money.