I would definitely want in a way I sleep outside pond water from the inside channel water. Otherwise you might find you are simply heating the outside pond which could be a great outcome if that's what you're planning on.
It looks like you're going to use the gravel channels as paths.
This reminds me of the way some people use mulch paths as swales.
If the pond is stocked with animals you're getting very close to having a passive
aquaculture setup.
Plant wise I would want to grow avocados,such a yummy fat!