Here is an (incomplete) listing of addons you may find useful to add to your Android device's Firefox installation for development purposes.
Via AMO: This add-on adds a "Copy Profile" item to your Firefox for Android menu. Selecting this menuitem will copy your profile to your sdcard, so that you can use adb to pull it to your desktop.
Profiles can be retrieved via:
adb pull /sdcard/mozilla_profile [<target directory>]
Via github: This extension allows you to dynamically load chrome code in mobile/android/chrome/content/ from a remote location. This means you don't need to rebuild to test your changes.
Gecko has built-in cross platform profiling support. This extension provides a front end.
Things that are not addons, but may help with them.
Pushes the given file as a Firefox for Android addon via ADB.