The only items on your list that I give to my chickens:
Broccoli (at least once a week)
Brussel Sprouts (occasionally)
Cabbage (at least once a week)
Kale (I feed em tons of this)
Potatoes (peeled, cooked and mashed - occasionally)
I stay away from giving beans and citrus. I don't eat okra so...
How does kale deplete a hen's calcium, what study are you looking at? Kale is actually loaded with calcium (amongst other good things) and probably one of the best leafy greens you can give to your chickens.