Engineers are normallly commisioned officers (Ground) with degrees
Correct
technicians are ground NCOs
Correct - although the branch was once known (correctly) as the Technical Branch, it was later re-named (wholly incorrectly) as the Engineering Branch
and Flight Enginneers are normally SNCOs who monitor Nimrod systems, in flight.
They are
Air Engineers, commissioned or non-commissioned and they do considerably more than 'monitor' systems.
The common denominator is that all are skilled professionals who work together within their distinct fields of specialisation as a team with a common goal.