Pets do not show missing buffs, maybe I've overlooked something but most of these pets are not buffed and should show me a Power Word: Fortitude icon.

Missing buffs on pets are not displayed on purpose, because usually no one buff pets, so all of those icons will be useless and too distracting.

I might be an exception to the rule I guess, I'm also a faithful pet healer and usually the pets are taken care of with prayer of fortitude.

Could there be a checkbox to turn this behavior on or off?

Update to version 2.6.9-beta, now buffs statuses have an option to display missing buffs on pets.