One thing, in the Air Force (At least on my base) E-4, Senior Airmen are supervisors and have troops under them. Not all are supervisors but usually, they are referred to as Senior Airman -insert last name here- not just airman. You should add "Stand by" into radio chatter.
A lot of people also join for the college. Also on paper e-5 and up are not supposed to be friends with E1-E4 but we all still are and drink together every weekend, I guess this just depends on the unit culture.
90% of the E6 to E9's I've seen here are either bald or sporting the old high and tight, not sure why but this is actually a thing I've noticed. They also talk about their bad knee or back a lot.
Each branch of the military is similar in some ways and vastly different in other ways. For example how units are divided up and what they are called are different, but tactics are usually the same. These differences may seem insignificant to civies but are important, especially for role play. That reminds me Civi is a good work you should add that is used commonly. Oh and Civi's as in "Go change into your civi's"
Good guide though! can't wait to see more progress on it! +1