Aww, sounds so sweet! One thing I read recently is that *domesticated* wildfowl will have holes in their webbing, but that's all I know about that. I assume it's to help tell the difference between domestically raised and wild ducks that are protected by law.
My babies are imprinted or attached to each other. Maybe yours has attached to you because there are no other ducklings around. (Forgive me, this is my 1st experience with ducks, so I'm doing a lot of guessing.)
I keep my babies is a huge Rubbermaid type box with pine shavings bedding. The box has holes in the bottom (more like cracks because it's so old), and that helps excess water drain out. My five are REAL MESSY. I have a low-sitting shallow dish in with them. They can splash about, and they also dip their food into the water. Next to the water dish, I have a jar-top with their food. Because they mess around in the water so much, I have to change their bedding every day. It gets completely soaked, and if I don't change it, mold starts to grow, and that's bad for their health.
My babies spend time outside. I have a 3-foot high dog exercise pen that I lined with window/door screening. It's in my garden, so dogs are other critters can't get to the babies. They have a large plant tray for swimming and bathing. I also put food out there with them. I'm very careful about it getting too hot for them or the sun heating up the water too much.
Here's a recent video showing the shallow water dish and food dish (jar top). The water is green because it's from a local pond and duckweed is floating on top.
Here's a video of them enjoying an outside swim. I make sure that they have a very shady side and that the water stays in the shade. This way, they can self-regulate how warm they want to be.