Alright, so currently it seems like the "Commonplace Guns" and "Guns Everywhere" options in character configuration are bugged as anything. First, feats with the prerequisite "Exotic Weapon Proficiency - Firearms" do not treat the prerequisite as filled even though the characters are proficient with Firearms. This makes taking a large number of essential feats for improving firearms impossible to use because "Exotic Weapon Proficiency - Firearms" ceases to exist. Second, for no readily apparent reason, the "Exotic Weapon Proficiency - Heavy Weapons" feat completely disappears under those two settings. This is kind of dumb and probably needs fixing. Just saying.