Assuming they are 18 months old:
1. Unknown (I'd lean female based on what I can see)
2. Male
3. Female
In CR auratus, the females tend to be longer and more pear-shaped than males. The size/shape difference really is not obvious until the animals are older. Also, at 18 months, I would assume there has been some breeding, or at least courting behavior. The female will follow the male around (as he calls) and stroke his back. My auratus really started breeding for me once I provided them with a small pond, and increased their humidity so it's constantly in the 80s +.