I don't think Qlink drivers necessarily object to 457 pilots in general, especially sim instructors.
What is concerning, is that the company will use this as a way to employ DECs. The current command requirements stipulate, regardless of prior experience (even on DHC8) you need a certain amount of company time.
What I believe the company intend on doing, is hiring a bunch of experienced DHC8 Captains as FOs, then removing the company time requirement (in lieu of DH8 time) to enable them to be upgraded instantly ahead of all current FOs.
And what happens in 1/2/3 years when the shortage grinds to a halt?