If they already roost in the coop, you generally don’t need to keep them locked in the run so they will roost. They will go in on their own at night. If some of them are laying in the nests they will probably teach the others where to lay. You can try free ranging them and see how it goes.
Adolescence can be rough, whether it is just pullets or a mix of pullets and cockerels or just adolescent cockerels with mature hens. Each chicken has its individual personality and each flock has its own dynamics. Sometimes you don’t have problems, but with your set-up and the ages of those cockerels (and I assume some pullets) there is a pretty good chance you will. Hormones run wild in the cockerels, the pullets don’t understand their role in the flock, and they are all maturing at different rates. With them maturing at different rates you might see a lot of readjustment of the pecking order. Sometimes you hardly notice this, sometimes it can get pretty violent. As someone once said on here, watching adolescent chickens is often not for the faint of heart.
You’ll notice I used some weasel words in the first paragraph, generally and probably. Especially when they are going through adolescence there can be a fair amount of violence when they are settling down for the night. The stronger may bully the weaker so much they leave the roosts and look for a safer place to lay. Often this is somewhere else in your coop but I have had some totally leave the coop and look for safer places to roost outside the coop. This has only happened a couple of times in all the years I’ve been doing this so it is pretty rare but it has happened so I say generally, not always. After they leave adolescence this problem usually goes away. Same thing with the pullets laying. Usually the new layers will lay where the others are already laying, but it is possible one will look for her own nest. If you run into problems with them confined you can try letting them free range to see how that works out. Most of the time you will be OK with them roosting and laying.
There is no magic number as to how much space you need in the coop or run. There are a whole lot more variables than just the number of chickens, flock make-up, and their individual personalities. In general, the tighter you house them the more likely you are to have behavioral problems. You can read some of my thoughts in the article linked in my signature below.
I’m also not one that guarantees you problems with multiple roosters. I recommend you keep as few roosters as you can and still meet your goals. That’s not because you are guaranteed problems with more roosters, just that you are more likely to have problems with more roosters. And I agree a rooster doesn’t give you a whole lot more security in a free ranging condition. Some roosters do sacrifice themselves with predators or fight off certain ones, but mine generally lead the flock to safety once a thread is established instead of taking on the predator. I think they do help some but the effect is pretty minimal. And as June said, it’s more of an early warning system but often a hen will take on that role in the absence of a rooster.
Many people keep multiple roosters together with the flock in varying housing arrangements and don’t have problems. Normal behavior for flocks with multiple roosters is that each rooster defines his own territory and has his own harem. By establishing different territories the roosters can avoid each other and reduce the chance of conflict. Usually they can even share the same roosting areas but it really helps them to spread out during the day. People can come up with exceptions to anything I say here, I’ve had roosters that did not behave this way, but separate territories and harems is pretty standard. In your run they do not have enough room to establish separate territories. In my opinion that’s where your biggest risk is as they mature. At seven months you don’t have roosters, you have cockerels.
With all that said your run is probably big enough if you free range them. Your run would be for emergencies, not something you’d use every day. Say you had a predator and had to confine them while you deal with the predator. Or you are doing something, either in flock management or on your personal life, where confining them is beneficial. In a recent thread someone’s free ranging chickens started visiting a neighbor’s yard and the neighbor was not happy. They had to quickly make a run to confine them while they built a permanent solution. Your run would probably do for short term emergencies. It would probably be OK for that number of hens and one rooster long term but keeping more than one rooster could become problematic if they stay confined in there. But I can’t say for sure it would be a problem. Each flock has its own dynamics. What works or doesn’t work for men might be different for you.
Good luck!