To add to your point, Mozilla publishes a clear policy on usage of its trademarks [1]. This has enabled Debian to maintain a rebranded version of Firefox called Iceweasel [2]
To be fair, when it happened, Debian rebranding Firefox as Iceweasel was an unhappy decision at the end of an acrimonious discussion. It's only with the passage of time (and by comparison to Canonical's obfuscation) that it looks like a clear and appropriate resolution to a trademark issue.
That's also true. Things weren't always like that when it comes to large organizations involved in FOSS development, but one would hope lessons are learned :-)
To add to that, Firefox sync work well with iceweasel at least in my personal experience. My understanding is that iceweasel is Firefox, just an older version with security patches as needed.
Iceweasel in Debian unstable stays up to date with the latest Firefox Extended Support Release, and Iceweasel in Debian experimental stays up to date with the latest Firefox release. Packages also exist in a separate repository for the latest beta and aurora releases, as well as of the latest release packaged for stable.