Banties are wonderful pets aren't they, so darn cute. Besides the first one, the other three are really too young to get a good idea of gender on for sure, give them a couple of weeks and it will be easier to tell. For the best guesses, good side shots where we can see the back feathers help...
How old are they? The two crested ones look like they maybe cochin and silkie crosses. The first one is probably a roo with the comb and wattle development, depending on age the Buff one is iffy also. You might want to see if you can get a side shot of the little cuckoo guy, is he also a...