Looks good, the middle plant is really nice you should be very happy. Can I ask what kind of seeds you're using? I believe they were KC something, are they f1s, f2s? I've noticed when I grow from seed I just have some plants of the same strain that just aren't the same, like the dud...it happens especially if the seeds aren't f1s or a stable line. So it could be something out of your control, also one of the drawbacks of hydro especially if it's a multi unit site, they all get the same light, water, nutes, etc. For your next grow if you use clones it will go smoother. Can you still pull the big plant out or is the root mass too big? You might want to consider moving it so she doesn't block out the little plants when the time comes.
Also topping if done and then followed with lower pruning will take care of the bush, the object being to get to get more than one cola. if you top and don't prune the lower area you get a bush. I am no expert but I top wait a week then prune lower section let it recover and flower. I get tall skinny plants with multiple colas, increases yield too....no bush at all. Plus the lower growth isn't producing anything worthwhile, just little fluff nugs.