Firefox code ought to be able to import data from an old Seamonkey or Firefox profile as well as data from other browsers such as Microsoft products. My Seamonkey profile isn't even old. I'm using the version compiled about a year ago because the two more recent ones crashed occasionally. There presently doesn't seem to be any code in Firefox to import data. Supposedly there used to be. It's still needed or very desirable. I don't have a question because it's pretty clearly not there. It's something for you to fix.