When can I start buying new puppy things? I am making a list of everything I want/need for the new pup, and am barely holding on to not shopping already.  

Also what is your water bowl situation? I am debating just getting a big "community" bowl for the dogs to share.

My dogs share a water dish. Just make sure that current dogs aren't going to be possessive with water before bringing in puppy. I would wait until a week or two before getting the puppy before I would buy too much stuff. Some toys and a bed you can get anytime, but things that are size specific like collars and crates I would wait until closer so you know about how large your pup is going to be before you bring it home, or make sure you get stuff very adjustable. Biggest thing really is don't get things so early that you get tired of tripping over them before the pup arrives. You don't want to get tired of their stuff with them not there and then pack it away where you forget it when you finally do get the pup.