Flowering too soon?

I have been in veg for about 5 weeks. During the beginning of the grow i was using a crap light from walmart then i went to buy a 400w MH. I am not sure what i did to stunt the growth of the 2 plants in the middle. I was gonna start flowering all of these in a week or so when the plants on the left hit about 12 inches. Do u guys think that the ones in the middle will flower as well? Or are they too immature? I only have one hydrofarm grow lamp with a built in digital ballast so when i switch to my HPS bulb they are all gonna be goin together. Just curious on what will happen to the ones in the middle?

If they have alternating nodes or show sex they are mature

Ahh so they still may bud? Just a low yield?

if you flip to 12/12 it will induce flowering, the size doesnt matter on that part, it will still happen what does matter is that it has to finish maturing before it does start flowering, which takes longer than if they were mature when flowering was induced. they will flower without a doubt, your just gonna be wasting 2-3 weeks though while they finish vegging and force mature.