Okay that plant MAY actually pull through but you've run into a pretty common problem with topping. You did it too far down the stalk. When you top, pinch, or LST, you have to be very careful not to expose the part of the stalk that is hollow. Just pinch off the last inch or so of the growing tip at most, if it's the main stem. If it's a side shoot and you are taking clones, you can take much more without running into the hollow part.
The rare times when I top low down, I IMMEDIATELY put a strong clip, like a binder clip, pinching the cut end of the main stem shut again so it doesn't allow dehydration, or allow disease to enter the plant.
The others look good. I can't say for sure whether that one will make it, or if the damage has already become irreversible, but if you can pinch it shut now...