Petsmart and pPetco have some decent cages. Petco has a Rat Manor that people have said they really like, and Petsmart has some nice cages, you can check out the rat cages at V, and the super pet ferret cages at
http://www.petsmart.com/family/index.jsp?categoryId=2769317&f=Taxonomy%2FPET%2F2769317&f=PAD%2FPet+Type+1%2FFerret&fbc=1&fbn=Pet+Type+1%7CFerret&fbx=0, including an FN.
Boys tend to be more mellow as they get older, but it doesn't really matter which one you get. Girls tend to be more active, and not quite so snuggly, but I have 3 girls who sit quietly on my chest while I'm on the computer. The personalities are something that you want to look for, and when they're young they may not have developed their true personalities. The breeder or rescue will be able to give you more information about their personalities. You know most of the rest of it.
As for bedding, you should be able to potty train your fur kids fairly easily. Most people here use fleece or something like it for the floors and balconies, and bedding or litter for a litter pan. The rats will pee everywhere, but it shouldn't be that hard to poop train them.
No clue about how long 33lb HT will last, and not had experience with Kim's Ark. Some people have had poor results in getting emails answered, but there is another place you can get them, I don't remember where it is, but someone else will post it for you I'm sure.
Now for the breeders/rescues, this is what I've found:
Breeder- Jessica Thorn, J&J's Cozmic Starz Ratz, South Milwaukee, (414) 570-0447 or (414) 526-2154
Moma Moondancer's Rattie Rescue, Milwaukee, (414) 352-5897
You can probably ask them about other rescues and breeders in the area.
The Milwaukee Humane Society has 2 male rats right now, Tim and Babyface. Tim is 3 mos old, and Babyface is an adult. You can see them at
http://www.wihumane.org/animals/smallanimals.aspx