Danube Crested Newts are presenting their sexes

I have a colony of 5 Danube Crested Newts.  I am now sure that two are male, one is female, and two are still deciding.  They are great.  They eat like pigs and are so very beautiful.  My pictures aren't great but I will keep trying.

Female in front with Male in back

Female on right and Male on left

These two are still deciding

Male- crest is coming in and tail is getting the prettiest shade of blue

There is only one other type of newt that I am really wanting- Alpine newt (apuanus sub species).