I have no clue on the gender of them, none really have any clear headspots or chipmunk stripes. The one with the super defined stripe is most likely a girl though. Out of curiosity, can I see a picture of the parents?
White legbars are colored white because of recessive white. Is it possible your stock carries recessive white? It is not the most uncommon. As they grow up, watch for tiny crests, and if they get crests, then they are white legbars
Frost white legbar is a hatchery re-branding. The proper name for a white colored legbar is 'white legbar'. The white legbar also can be autosexed, it is just harder, and most breeders don't breed their white legbar stock for autosexing