Hello.IMHO most proper way at the moment is to modify install script existing in Mozilla distro - so it asks place to install and modifies UserSetupScript with EXACT/full paths to app dir, instead using %A.
something like: */apps/Firefox/components SD
Also dynamically loaded libs are loaded with absolute path, so only those linked by firefox-bin directly is needed to launch. OTOH, SSL has a few library checks to make sure it is not compromised, so special care is needed there.