Without compiling, you can unzip, change and zip some JAR or JA files to change the title.
http://kb.mozillazine.org/Rebranding_Firefox The exe can be renamed just like any file and works fine.
Changing the icon can be done with an icon changer or "resource hacker" software
https://www.howtogeek.com/75983/stupid- ... .exe-file/ as long as Firefox does not use a built in checksum which I don't think it does. Note that all of these changes will / may be undone if you let your modified Firefox update.
But, you can compile Firefox. You will by default get a browser called "Mozilla Browser" instead of Firefox I think. For most Windows users compiling will be a pain, I'd expect figuring it out to take a typical user a full workday.