Don't know the answer to your second question, but it would be impossible to do what you suggest, i.e. commute between Europe and the Gulf, especially if you have a rostered based position that requires minimum rests, etc to be observed, and even more especially if you need to rely on discounted ID travel to carry out the commuting.
If you are rich and can afford full fare seating all the way, maybe you can.............
What position are you speaking of anyway? Cabin, cockpit or other?