Brooder setup questions

I'll be getting nine babies in February. Only four are mine, and I'll be fostering the other five for my aunt until her coop is ready. They don't have space for a brooder in their house, so I offered to keep hers with mine till they're big enough to move to the coop outside. Aunt will give me the money to buy their feed and supplies while they're living with me. She lives about ten minutes away from me and will probably be over with her last remaining homeschooler (he's 12, his brothers are in high school and college) pretty often while the chicks are still in the brooder, but I'll have most of the care and keeping of them until they're ready to be outside full-time.

There's a mix of breeds but they're all standard size, no bantams. I'd planned to brood them in the garage, safely out of reach of the household pets, which include a cat who likes to hunt and five dogs who are all sniffers, but will otherwise leave tiny animals alone. Still, I don't want them in the house, just in case. How much space do I need to allow for nine chicks to grow from day-old teenies to fully-feathered pullets?

When do chickens start to establish a pecking order? Is it wise to brood all nine together when five of them are going to move away after a few weeks, or would it be better to brood our flocks separately?

I had planned on watering my chickens with nipple waterers right from the start, to eliminate bedding and poop in the water and reduce/eliminate drowning risk. I don't know how my aunt plans on watering her flock; will they adapt to using standard waterers when she gets them?

What do I really need to successfully brood chicks? There are so many things on the market that You Must Have To Properly Brood Chicks, and I'm sure I don't need all of those things. Can someone give me the basics that will get us through the first several weeks without too much fuss?

 

Thanks so much! I know it's early yet, I just reserved the chick order today, but I want to be prepared well enough in advance that I don't have any last-minute things I forgot or situations I can't fix.