Being a fan of Python, I am also trying to work on some Mozilla Release Engineering bugs, but run into problems trying to replicate the dev environment used. This area, while interesting, is not as well developed in terms of documentation or process for outside contributors; their wiki information on setting up a dev environment is somewhat geared towards Mozilla employees.
But while I haven't made any real headway on any release engineering bugs yet, I do have a partial dev environment up so that I can attempt to tackle a subset of their bugs, mainly the ones that don't rely on having permissions to Mozilla's massive build infrastructure. I also want to get involved with Autoland after reading Lukas Blakk's (a Mozilla Release Manager) blog post on Autoland.
All in all, I feel like I am well on the way to becoming a full-fledged Mozilla contributor.