So, ignoring the comedy routines and in a completely out of character attempt to actually help the guy -
Disclaimer: I'm ex-RAF, I 'visited' the RN off and on over a fairly long career (on board various ships I regularly enjoyed using words like 'Floor, ceiling, wall, door' as it invariably drew the expected reaction....my favourite was the day I said 'I'm not lugging this up 6 ****ing floors' on RFA Argus).... so this is a bit of an outsider's view that I hope the dark blue will modify and correct:
PO: pretty low on the food chain, expected to know his a**e from his elbow on the kit he's meant to operate, limited supervisory function. Some PO's might well run small sections of lower ranks, but this guy doesn't tell too many people what to do most days.
CPO: Whilst still expected to do stuff and work the kit properly, expected to be a professional who can supervise lower ranks very effectively, may have a training role, the sort of person who forms the NCO backbone of most competent military forces. Irregularly advises junior officers on protocol. (This often takes the form of an arm round the shoulder after alcohol intake, when the officer is debriefed informally about his man management and leadership skills).
Subbie: A sort of fledgeling, often given odd jobs to help develop character, leadership, common sense - you know, the sort of chap who gets a leaflet entitled "So you want to be the VD officer?" in the internal mail. Given SOME responsibility to see how they handle it, but seldom left to conn the ship through fog banks unaided. About on a par with the PO in some ways, but allowed to wear a nicer hat.
Lt Cdr: Probably in charge of something - perhaps even the squadron, at least temporarily. A senior officer (only just, which means that when REALLY senior officers get together it's the youngest looking Lt Cdr who has to make the tea). Essentially somebody who will be a sqn exec, not just another pilot/ohbserver. Often allowed to talk to the captain. (eg 'One lump or two, sir?)
Protocol - CPO's will believe themselves superior to all except the Lt Cdr, who they will (grudgingly) allow to have the last word if they insist. Lt Cdrs will figure they're top of the tree. It's a toss up, but I'd have to say it'd be a very confident subbie who decided to put a CPO in their place. Subbie v PO - decided either on 3 falls, a submission, or a blowback in Uckers.
Both the subbie and the PO would be expected to make mistakes and need guidance - the subbie more than the PO I'd suggest.
The subbie has better promotion prospects than the CPO and PO.
None of the 4 can afford to get carried away on 'Talk like a pirate day'.
Do let me know if you'd like my guide the the Army at any point
Dave