Welcome to BYC and duck ownership. I've noticed a dearth of replies here lately too. Maybe it's spring fever.
I've had ducks and chickens for a few years now. Not an expert, but did my research and have a few years duck keeping under my belt.
Nice looking ducklings. I've not heard of that breed.
As for food, you can feed chick starter but make sure it is NOT the medicated kind. That medication can kill ducklings. You can finely chop greens (not spinach), or frozen/thawed out peas, or even chopped dandelion greens and float them in the water bowl for treats, too. They will need some chick (not full-grown chicken) grit added to the starter. If you can find higher protein chick starter (try turkey starter) at about 20-22% that's better. Mine did OK on the regular 18% chick starter, though.
Rather than a chick/chicken waterer, I use a bowl. Crockery works well as it's heavy and they can't tip it over. Don't be surprised if they swim in it, just make sure they can get out. You WILL be cleaning the bowl out a lot. I'd say my ducks are about three times as messy as chickens, mostly due to the water factor. Ducks always need to be able to dunk their entire bills/nostrils into water to keep them clean. Thus, chicken waterers really don't work well for them.
Ducklings need more niacin than chicks. I bought a cheap bottle of niacin caplets, the kind you can take apart. Add 100 mg of the powdered niacin to a gallon of water. I just mixed up a gallon jar full of this and used it to refill the water bowl.
Make sure you have pine shavings or some other non-slippery footing for them. Otherwise they can get splayed legs.
Ducklings grow WAY faster than chicks, you'll be amazed. They're about adult size at two or three months. Start the heat lamp at 90 in one end (so they can get away from it if need be) and reduce by 5 degrees per week. If they constantly are trying to get to the cool end, they may not need it anymore. You can put a pan of water in there and they will swim in it. Only supervised, though, as without adult feathers they can get waterlogged. And they MUST be able to get out of it. You can just put it in there for a while for your entertainment, then remove. Nothing cuter than swimming ducklings. :-)
Once they're fully feathered you can provide sprinklers or a wading pool for them. For my adult ducks (and chickens) I lost the chicken waterers and just use the rubber tubs you get at feed stores, or buckets. Much easier.
Have fun and good duck luck!