Question mark characters (missing fonts)

As the upgrading issues (new computer!) continue - I can't seem to fix the question mark (replacement font)/hieroglyphics issue. I'm using Suitcase Fusion 8 - I've already cleaned out the cache and checked all fonts. I've used Fontbook to validate the fonts. I've also used the Fontbook 'Restore fonts' command. Nothing. Still getting this in Mail (and sometimes, Text Edit and Firefox):

Any ideas? This is infuriating.