Why would the favicons be hidden? If they are in the profile (and where else would they be?), then the file would be in there. I did not want any favicons in my bookmarks, so I tried locking the Favicons file and that did the trick.
I think u should be able to add --that-location-flag to Windows registry.
Either way - check Browser Chooser 2 (open-source). With that other apps and installers can't open browsers as they want, external links need validation by keyboard/mouse/touch (like in android).