Re: I've always had some issues with file paths
For the login.php, that's what the Replacements section of CMPS/Gallery is for.
For ranks, unfortunately, vBulletin ONLY allows relative paths for them when you define them, so I don't know if there's a way around that. I notice that Ranks don't show up (even as broken images) when viewing the comments on my site, so I thought that they were just not included with the gallery postbit display. You're seeing broken images for those?
For smilies, you need to edit all the smilies and put the full paths. (Or re-run the CMPS/Gallery install script and choose the option to update the paths for you.)