I use glass dishes that I get in two sizes. I pick them up second hand so I am not sure if they were made for food or candles originally but they have a wide base so they are impossible to tip.
I wet their food in one and put clean water in the other on the other side of the narrow part of the tub to confine the eating mess to one end of the tub away from their sleeping area. The feed is Flock Raiser crumbles that is wet down to a mash consistency. I use any left over water they got food in while drinking and cleaning their bills to wet the dry crumbles for their next batch of food.
I do feed and water several times a day so when their food is gone I make a new batch and freshen their water. I don't mix big enough batches of feed that it will get moldy and they don't poop in the dishes because the dishes are a little higher than their butts. They don't really step in the food or water much because the dishes are in the corners of the tubs and the dishes are big enough to get their bills in to scoop food and water but not big enough for bathing. I have seen some PVC feeders and waterers I like the design of but they would not be very easy to keep clean. I don't use disposable anything because I reuse my set-up year after year.
I give the ducklings supervised swim time for bathing and exercise. I usually have a clean tub ready when they are done but sometimes if all the tubs are in use I clean the tub and they go back in the same tub. They are easy to clean out in the bathtub with our handheld shower attachment. The glass dishes are also easy to clean and they can go in the dishwasher to sanitize them. I use antibacterial dish soap and a scrub brush to sanitize the plastic tubs. People who use bedding for ducks so often complain about how messy they are but ducks are very clean if you let them have regular access to water with nothing that will get soggy and stink.
I spend time with my babies to socialize them so I don't have them in a dirty environment and leave them without care for days. Ducklings do take regular care because they are babies. Once they go outside they are more on their own but as babies they need more care. I love our ducks so I enjoy spending time taking care of them. I do not want them to imprint on me because I want them to be ducks but I do socialize them so they know my voice and are calm around people (until we get out the net, lol).