the seeds you listed sound okay, since they are more like a food/fleshy material rather than hard seeds. I can't find any info on Millet, and my ducks have had it before. I think they are small and are okay in small quantities.
Peas, grapes, berries etc with seeds should be okay.
I wouldn't...
Throughout my dealings with ducks, I have compiled a huge list of good and bad treats you can feed your ducks and geese along with their feed.... This list has been throughly researched online, from books, etc. I don't make this stuff up! lol.
Diet Supplements: can be fed something from...