You can let them swim in the sink, or get a tote or tub of some kind and fill it with water. Not full, but just enough that they can stand up, at least till they have their feathers.
Anything that is dark green is good for them. Iceberg lettuce has little to no nutritional value, so that should be avoided. You can use frozen peas and drop them in their water to make them dive for them, they love that! I don't know how prominent dandelions are where you live, but if they are as thick there as they are here you can feed the greens to the ducklings too.
Contrary to popular opinion, ducklings don't have to have deep water for drinking. There are many people on here that use water bottles for them (like you would have for a bunny), and they do just fine.
Non-medicated is best, but they can have medicated if the only meds is Aprolum (sp?) Ask Katy, she knows which meds they can safely have. If you can get non-med feed it would be better.
If you can't find waterfowl starter, you need to get the highest protein chick starter you can find. I use flock raiser, it has 20% protein. They will also need brewer's yeast if you don't have waterfowl feed.
Ducklings need about 90 degrees in the brooder for the first week, then lowered weekly by 5 degrees,
supposedly. Mine are now 2 1/2 and 1 1/2 weeks old and haven't had any type of heat light for over a week. The little one hasn't had any heat since we have gotten it, and it's doing just fine. The less heat they can comfortably handle the better, as it will make them feather out better.
I can't think of anything else right now, but if you have any other questions, just let me know!