There are actually a number of things that will give you various bumps in enlisted rank. One, believe it or not, is being an Eagle Scout- automatic bump to E-2 on enlistment.
These days, or at least in 2007, they were making college graduates E-4 after basic training- my buddy enlisted with the intent of going to OCS, and after Basic he was an E-4 for a short period before starting OCS because according to him, he has a bachelor’s degree.
Different services have different standards, but when I joined the U.S. Army Reserves in 1999, I got an automatic bump to E-4 on enlistment for having a B.A. During Basic, all of us were simply Privates - no rank insignia, we were all addressed as “Private”, and so on, but I was paid as an E-4.
The lowest paygrade, not rank*, is E1. You describe a situation where forfeiture of pay and allowances is expected; there’s not a separate pay grade for not being paid. The proper form of address for those in disciplinary barracks is “Inmate” regardless of paygrade/rank they’ve been reduced to. A policy memo from Army Corrections Command in 2010 shows recent standards for prisoner uniform. Note that wear of rank insignia is not a part of the approved uniform. Rank doesn’t mean all that much once sentenced to disciplinary barracks.
Ranks and paygrades are related but not the same thing. They don’t have a 1 to 1 correlation in the US Army. Paygrade E4 has two associated ranks, Specialist Corporal, with their own rank insignia as one example. Stranger on a Train was actually incorrect before this came back to life. E9 is another example. Both Sergeant Major and Command Sergeant Major are considered ranks with a separate insignia of rank by the US Army. The term of address is the same, Sergeant Major. Someone of lower rank, as he pointed out, can still be in a position to perform the duties. You do need to be in the CSM duty position to hold and wear CSM rank so it’s on the confusing side.
But a CSM doesn’t outrank a Sergeant Major either- it’s kind of like the Spec-4 / CPL difference at E4 in that a CSM is an advisory position to senior officers and a regular Sergeant Major is more of a line NCO position.
E-8 is either a First Sergeant or a Master Sergeant. 1stSgt is more administrative, while MSgt is for one who chooses to remain in their technical MOS. Neither outranks the other.
E-9 is either Sergeant Major or Master Gunnery Sergeant. SgtMaj is what 1stSgts get promoted to, and hold administrative billets, and MGySgt is what MSgts get promoted to, and they’re still in their technical MOS field. Similarly, neither outranks the other.
Generally speaking. There are exceptions, such as a MSgt holding a 1stSgt’s billet. This was back in the 80s and 90s.