Wrt
If AEU had to go into the market place for pilots to crew the bmi operation, then it would make sense to use anything bmi could offer; captains and F/Os.
Uhm, therein the really interesting bit would be how to handle the undoubted disparity between BMI's & AEU's pay scales & T&C's?!
One can certainly envisage a situation where there are two pilots (1 BMI and 1 AEU), of the same rank, flying in the exact same aircraft, on the same route, but being paid different rates / allowances... and that's really going to go down like a lead balloon, isn't it ?!