So in short it's a doddle to qualify so long as ya learn your stuff? Whether any GS would wanna hire you tho is another matter... hmmm, interesting...
Most ATPL groundschool instructors tend to have cut their teeth on military aircraft or have airline background don't they... I wonder how many just have a PPL but with a professional teaching background? Not many I imagine. But the biggest thing that sifts the wheat from the chaff must be the desire to wanna gabb in front of 20 odd eager airline wannabes for 4-5 hours a day! A sore throat must be the least of yer worries!
VFE.