Yes it would be more logical to take type rated and experience pilots from VIrgin ect if as some point the A380 and B787s are coming back and you are going to lose pilots out of your operation.
But if Alan is going to kill the mainline operation for good then there will be no seats to come back to. So any QF LWOP pilot to Alliance will probably end up staying.
Again if the training costs are covered by QF, Alliance won’t care about crew turnover. Has no impact on costs