yes they are stretching,, good thing they are still standing up, I say go ahead and transplant into the 1 gallon containers, and when you transplant, put the roots a little deeper than they are now, put about half of that long stretched stem down in the dirt, the dirt will hold them up,, then lower your light,, keep it on half power,,bring it down to about 24 inches above, maybe even 18 inches, then a few hours later check on them, if the leaves are not twisting your ok, you will be on half power for several weeks, plants dont need nearly as much light during veg,,
good job keeping your eye on the soil,, the ffof will take good care of your roots, stick your finger down there a couple of inches,, if it feels damp or wet,, dont water yet,, good job resisting the urge to over water and the urge to throw nutes at them,,,
the one gallon pots will take you almost to flower,, what I do is UP Pot them when they are teenagers, around 10 to 14 inches tall,, into thier final containers, that way they get really fresh ffof and then you dont have to ad any nutes for 4 to 6 weeks, sounds strange i know, but you will get nute burn if you start adding before you see any signs of nute def, and you may never see any,,, I did ad garden lime to my ffof this run, and I am going to use some Happy frog bloom nutes organic ( not the soil ), its got simular things to the ffof but in an organic concentrate,, then you can make teas later on and water them with it,, or you can spread it on the top of the dirt and scratch it in a little and the water takes it down into the soil each time you water, and because its all organic you dont get any ph issues or nute lock out like some people do when they use the "salts" type nutes with ffof
hope this helps,