OK, I'll punch it up a bit.
The fish in the first photo are the most interesting to me. The one at 12:00 o'clock has the worst pattern and gives an initial appearance that the Hi is at risk of fading. But, I think that is a misperception. This fish has a strong shoulder, looks to be female to me and I'd guess she will be growing well for a number of years. But, I would not want her because of the pattern. (Pattern is least important in judging, but is quite important in my decision of what I will have living in my pond for a decade or more.)
The one at 3:00 is the stand-out today. I agree with DickB that this most likely male, but never can be sure from a photo at that size. Enjoy this one now. In two years, I think you will start finding him boring.
The one at 6:00 is my favorite of the group. See how the Shiro glistens? The Hi pattern is the most interesting of the group, with decent odome. Right now the Hi looks a bit messy, but I think it will clean up. The Hi also looks lighter. I cannot tell if it is thinner or simply too immature to show properly. The way the Hi cuts across the shoulder and the deep sashi reminds me of Hasegawa Kohaku. Then, there is the Hi in the pectoral.... not too much, but if you believe the notion that Hi at the base of a pectoral indicates strong Hi that will not fade, then this can be seen as a positive (albeit unfortunate) indicator of the future Hi development. So, altogether, I see the Hi as most likely immature and would assume future improvement. Then the most important factor: the body. The photo angle is actually pretty good for this purpose. See how broad the head is between the eyes? And, it has a flatness to it?? I think this fish has the genes to grow to be large.
Then the one at 9:00 ... Well, I already took 6:00 home with me, so I'll let you guess at my thoughts on 9:00.
.....Seriously, I am not able to evaluate these fish reliably from a photo. But, it is fun to guess. If you jot down your guesses now and then review your thoughts in a year, I think you can learn a great deal about koi development. It really helps to see the living fish in person!!
Enjoy.