The only way to accurately check their genders would be to either observe their behaviours or vent sex (the latter is the better option) them because its rather difficult to tell the gender with these feather colourations. Button Quail are monogamous so once breeding season, and the right age hits, then they'll break off into breeding pairs or the males may fight over a female to the death, so be prepared to separate these guys if there turns about to be more than one male there.
#2 could be a male because of the 'bib'-like thing on their neck, but then again, it could also just be a random splotch so I believe it might be a she.
The others, I have no idea.
They could potentially be all female.
Just check their butts under the tail feathers. Females have a larger opening than males. If they recently laid any eggs, then it'll be easier to recognise the size difference.