I can see the nute burns on the lower picture from when you fed them while too young. They look healthy now. Your temperature is on the "too warm" side, as the ideal temp is 75F. To me, they look like they were put in the net pot about 2-3 weeks ago.
Although they were clones, none of them will be like identical twins. The reason they are not the same size could be from any number of things from coming from different mothers to one being closer to the light etc etc. You will not be able to determine sex until they have been in flowering (lights at 12/12) for about 10 days. CFL's and T5s should be about 3 inches from the plant a MH should be farther away, depending on its size. At this stage, you will have the option of letting them grow a bit more and take some cuttings from them, then as soon as they are well rooted, flower them to see what sex they are. Make sure you tag each one so you know which clone was taken from what plant so you can destroy any males.

good luck!
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