Hi efosb!
Well, I may be able to answer 1 & 2.
As a test I went into my default folder and removed
menu.bmp and
menuicons.cfg and then restarted my browser. Next I checked my menubar dropdowns and all the icons were gone. Since the browser started without errors you could probably simply remove them in this fashion?
This being the case I think you could logically go into the default folder and remove
main.ico as this is what puts the icon in the upper left as well. I don't know for sure as I didn't take my tests that far.
I run off a file in the theme folder and I'd have to start moving a bunch of files around to test that and my time is somewhat limited. Best guess would be to give it a try by removing the file to a temp directory and restarting the browser and see if you get any start-up errors, etc.
As for 3 & 4 I'll have to let someone with more experience with the project answer those ones.
Happy motoring!
Eyes-Only
"L'Peau-Rouge"