Well, there are as many different set ups and ways to keep flocks as there are flocks, so far be it from me to tell you how to manage your birds!
I would say, though, there are a couple of things I've learned about keeping chickens that you may want to keep in mind.
First, chickens are happiest and healthiest when they have as much space as possible to move around. Unless there's a specific reason to cage roosters (like for breeding or show), I don't know why you'd want a whole host of birds living cooped up, who you're having to feed and clean up after, and serve no real purpose in your flock.
Second, hens are happiest, and the flock is most orderly, with a rooster or two roaming with them. I understand that there are a lot of people who cannot keep roosters for a variety of reasons, but if you're able, a good rooster or two with your girls generally keeps good order. To have 18 roosters, and keep them all caged, doesn't make a lot of sense for good flock dynamics.
I know you've said that you're ordering that many roosters so that you have extras if some don't make it, and you have an active poultry community to trade extras, but you really might want to rethink that. Although you might be able to give away a handful over time to people who lose one for one reason or another, most poultry keepers will be as glutted with them as you are.
Again, if it were me, I'd order 2 or 3 roos total, and see how you do with those. If you decide you want more over time, they should be easy as can be to acquire-- you've said you live in a large poultry community, and the breeds you've chosen aren't uncommon-- you ought to be able to have your choice of giveaways of any of those breeds later on in the season.
Good luck with your flock!
