I have no direct experience with your approach, but I may have some useful input. I do have an in pond pump that I do use sometimes for landscape garden watering. I believe the pump was specifically designed for ponds because it has a long power cord, but you could probably use a sump pump instead. They generally have flat bottoms that take diffuse water input that is then directed to 1.25 or 1.5" output connector. I don't recall my pump's flow rate, but it puts out a real gusher if the input was sitting just underwater for testing; a gusher that would allow you to empty a pond in a few minutes if the water was just thrown a foot outside the pond. However, my gardening water storage pond' pump is actually connected to ~50' of essentially 1" pipe and then on to a long garden hose. all this resistance drops the actual flow to a gentle hose stream that would not be effective with even a small sprinkler. My solution was to add a medium in line (pipe or hose connectors on both ends) transfer pump. I am now using a small 1/4 HP one and before was using a 1/2 HP one that failed (not too surprising since it came from Harbor Freight). The transfer pump is connected where the garden hose begins. It dramatically increases flow although still not a blast out of the hose or anything, but it makes the hose reasonably useful.

On to um fertilizer; I very much doubt that you could eventually use drip line, at least not the ones with fittings. I used drip line many years ago on city water and found that the drippers clogged up. Good luck with all the extra crud! But you certainly could move one or more hoses around or connect them to sprinklers. You certainly wouldn't want to use sprinklers with fruits and veggies, but I suspect that direct to ground hose watering would be OK. However, you should probably check with the Vegetable Forum for current thinking on that.

There could be issues with Salmonella. I've heard that you need to be careful around ducks because of the risk of Salmonella so that washing hands thoroughly is very important. That suggests that water from duck ponds wouldn't be good for use on vegetables. But I've also heard that chickens are a higher risk than ducks. For me I wouldn't use it directly on anything you want to eat. Better to use it on ornamentals to be on the safe side.