Welcome Coloradochick! Oh, it's so sad that you too are now going to be draw into the addictive world of chicken keeping. You're going to be one of us now. CONGRATS!!
Those three breeds should all do just fine out here. I have Australorps and they are wonderful. They are very friendly, we pick ours up and pet them pretty much every day. My children have raised our chickens so they are very people friendly (except my SSHamburg - that's just a flighty breed, although she will let me pet her sometimes ... it's just on her terms.). I am going to get Brahmas this coming year. I also have RIR and Red Sexlink which are also very, very friendly and great egg layers. Sexlinks are one of the breeds that start laying eggs at a younger age (around 17-18 weeks many times) so that was nice to get those eggs weeks before the rest of my girls started laying.
It's great to see you doing your homework before getting your chickens. That will save you possible headaches and make things much better for your chickens. My biggest suggestion is to make sure you have their chicken house and enclosure (whatever that is going to be) done and ready when you get them. Go overboard on protection from predators from the beginning and hopefully you won't lose any chickens.
It's also great to have another stay-at-home mom here.
I live SE of Elizabeth so probably an hour and a half or so from you.
Search the board here for your questions, most general questions have been asked and had many good answers, if you can't find an answer to a question then please ask -- lots of people here with far more knowlege than I have will give you great advice.
Have fun!