Elisha - I think you misunderstand a 1-step versus a 2-step. A 1-step surgery involves what you described - taking the colon out, making the jpouch, and hooking the jpouch to the rectum ALL in one surgery, eliminating the need for even a temporary bag. A two step just splits it up - I believe they do make the jpouch on the first surgery, but wait a while to hook it up to let it heal, meaning a bag would be used until the takedown. I've heard of the three steps method, and thats for really sick people.
Fortunately for me, I am young and healthy, as far as intestines/colon go (need to lose a few pounds though :P ), so I think there is a good chance of a 1-step for me. The thing is, though, you can't be 100% sure you will have a 1-step. The surgeon wont know if he/she can do it until they open the person up and evaluate several qualities of your colon/intestine. So make sure you and your sister are prepared for the possibility that a 2-step will be needed. Good luck to your sister :)
Heh, in these couple days I've done a lot more research and know more about the whole 1step 2step thing than I did - though if I got something wrong, PLEASE correct me! I don't want to give anyone false information! :D