Mozilla, the application suite as you know it from Mac OS 9.x has been superceded by
SeaMonkey. Firefox is the stand-alone web browser, just like Thunderbird is the independent email client maintained by the Mozilla Foundation.
As I have never used SeaMonkey, nor Mozilla for email, I cannot provide specifics for a migration of data and accounts from Mozilla, but I suspect that its import function works in ways similar to that in the various Mozilla iterations. In fact, the
online documentation of the current version, SeaMonkey 2.4, states that it will offer to migrate your data from SeaMonkey 1.x or Mozilla 1.x at the first start after installation. You might want to ascertain exactly what 'your data' entails, I can't say for sure.
As an alternative, you can set up Mail, Mac OS X's email client, for your various email accounts now handled by Mozilla. Most ISPs have web pages with detailed instructions on how to set up the current crop of email clients under various OSes.
Useful links:
-
SeaMonkey-
Firefox-
Thunderbird
