I see a couple things not answered, the nipples (depending on type) will require a regulator if connected to a live source of water to avoid blowing them out. There are nipples and there are small cups. The chickens don't care which you use, it's human preference.
More or less nipples are not that important unless you have a huge operation. Chickens will often all run together to a nipple to drink together (silly girls). So, it wouldn't matter if you have 1 nipple or a dozen. If you have a "lot" of chickens it doesn't hurt a thing to have several but you never know if they're all going to like just one of them (silly girls). If you have a nasty dirty pan of water or a puddle of water in a mud hole, they love that too (silly girls, lol)
You all do what you want. It's all our own preference, not the chickens necessarily. As long as the volume of water supplied will meet their needs and not run out, you got it taken care of. Chickens are smart, smarter than we are sometimes, and will drink when they're thirsty, at the most convenient spot and all it takes is for one of the girls to run for a drink and they all may run for a drink together. They're so cute
If you have a nipple system, don't worry, they will find it and when that smartest hen in the flock gets that first drop of water, they are all watching and have to try it too. I've always used hamster water bottles to start my Serama chicks on and they graduated to a rabbit water bottle (it holds more water so there is more pressure on the ball at the tip and too heavy for the teeny Serama chicks to budge at first) but if there is a dish of water, they figure that out too. They are all smart and curious and it takes a couple of seconds to learn any of them.