Inside the .mozilla folder is a SeaMonkey directory, the same as if you had firefox install a firefox directory would be inside the .mozilla folder. Copying the seamonkey directory to the .mozilla folder and launching seamonkey should work without issue, I doubt that renaming the firefox directory to SeaMonkey and then launching SeaMonkey would work though.
I installed a theme, but it's still the elementary icon set. I manually configured, fehlstart to match the theme. That theme really did change alot. It is a very well built one. I borrowed it from BodhiLinux. It's their Bodhi-Forum GTK theme. I just Like it.