My plants are dying. I need to do something drastic.

Here's the setup - 
 
First time grower here.
These are the mystery seeds that came with my first order. I'm pretty sure they're a haze variety, due to the super long flowering time and the shape of the leaves and stalks.
 
I'm using an ebb and flow hydro setup built in a 2' x 5' x 8' closet.
 



 
I vegged for 8 weeks, which I now realize was way too long. These girls have gotten hugely out of control. They've been in 12/12 for just over 10 weeks now, and they still don't look close to finishing. Some haze strains I've read about can take up to 16 weeks, and that's making me nervous.
 


 
I'm using General Hydro's Flora series, using about 60% strength of the formula on the bottle. I water three times a day during the light cycle. I've got them under a 600w HPS running with the ballast dimmed to 50%.
 

 
I have two plants growing, and they have gotten massive. I didn't scrog correctly at all, so they've grown about two feet past it. I tried tying them down for a while, but now I'm just cutting off tops as they get too close to the light. It's been foxtailing like crazy, so there are dozens of smaller stems growing out of the bigger branches. It's incredibly thick, so there's no room for air to circulate.
 
Over the last couple of days, it's just felt like they've been dying. I'm seeing lots more leaves drying up and falling off, there are burnt tips on the ends of a lot of smaller leaves all over the grow, there are yellow leaves on the upper branches from being too close to the light, and when I move them around, lots and lots of pistils and leaves and dried up bits fall off. 
 

 
I'm at a loss and am fearing that I may lose the grow altogether.
 
What can I do? Should I try cutting all the tops off at a certain height so air can move easier?
 
Should I cut out a bunch of the branches to give the others room to grow?
 
How do I get them to finish flowering? I'm seeing trichs forming, but there aren't a ton of them and the buds are taking forever to fatten up.
 

 
I'd love any advice I can get from the experts around here.
 

 

Another problem. The heat is causing some hermie issues. I just found a sprouted seed in my ebb and flow tub. My guess is that it's no more than a couple of days old.
 
I'm going to start by flushing. I put 10 gallons of RO water in tonight. They go through a little more than a half gallon a day. I'll make sure they get lots to drink.

 

You're confirming my fear. There's no way I'll do ebb and flow again. Next time it'll be RDWC. And I'll be using known strains instead of the freebies.