A couple things come to mind:
First off, if you're going to use a child's swimming pool, you'll have to find some method of keeping sunlight off the water. If you don't, you'll have algae galore.

Second, leafy vegetables grow best on rafts, but watch out for stuff that grows tall as it will eventually just tip over.

An aerator will dissuade algae formation as well as boost your plants' growth.

Thanks for the information.

A question about the algae. To keep light from entering I plan to bury the pool nearly up to the rim (but in such a way that it's still higher than the surrounding ground) and to cut the raft so that it covers nearly the entire surface of the water, leaving just enough space around the edges for the raft to move up and down. Some light will enter through the edge, and through the net pots at least until plants fill them in. Should this reduce light enough to prevent algae growth? Aside from the aerator, is there anything more I can do?

Bill