It's hard to sex them when they are juvies. Females usually have a low voice and males are a higher pitch.
Males will also be a smidge larger than females. I believe you have a pair. The blue banded one appears to be a male and he is shielding the female from you in the first two pictures. If this is in fact a male, he will continue to keep her away from you to protect her.
Your other option is to vent sex them or give them a pool and see if they start breeding, it's the season.
My birds started breeding last week and usually I don't get eggs until the end of February.