I've kept fish since I was a teen along with ponds, have 2 now for about 30 yrs now. The aeration will keep the surface ice from forming in the winter along with a small pond heater and in the summer increase the gas exchange at the surface by rolling the water. Plus that will keep the larva from breathing at the surface since they need still water. Look into aquarium sumps for ideas about having your plants separate. I've had several large tanks set up for years with homemade on-the-back filters with plants doing all the filtering for the tanks. With the ducks, with the amounts of biological debris produced a large hydroponics setup might be needed to clean the water but it could be done.
