Do you coach tackling properly at U7?

Yes, I would coach it — just in small doses and inside games. If players are swinging a leg wildly, give them one or two useful ideas: slow down as they get close, stay on their feet where they can, and try to get their body close enough to actually win the ball. Then put them straight back into 1v1 or 2v2 situations where they can try it. I would not run a long technical tackling drill with children waiting in lines. 3v3 gives you loads of natural defending moments, so use those. Freeze one picture very occasionally if there is a safety issue or something everybody needs to see, then play again. At U7, a simple defending habit they can actually use is worth more than five detailed coaching points.