AIX Firefox CD
When you're installing AIX from scratch, it gives the option to install Firefox automatically with the (optional) Firefox CD as part of the final installation for AIX 5.3 and 6.1. As this CD is rather hard to find, there is an ISO of the image included here. It happens to contain Firefox 3.5.8 (which isn't the latest version of Firefox for AIX--the latest being Firefox 3.5.16-2), however this will automatically install all of the dependencies in the correct order and have a working build of Firefox for your installation ready soon as you log into the desktop.
Note #1: you won't be able to use Michael Perzl's packages if you use this as they are built in an incompatible way. You would have to work the other way around by installing Perzl's packages and then the surrounding AIX Toolbox ones from there.
Note #2: IBM removed the ability to use this on the installer on AIX 7.1+, so the browser would have to be installed manually anyways.
Downloads
--> Mozilla Firefox 3.5.8 CD-ROM for AIX