The future of the Avro is the big question mark around Mesaba. Right now, hiring is only going into the CRJ. Supposedly on Oct 6 we will find out more answers. So until then, we hold our breath.
I would suggest applying to other regionals, not because Mesaba is a bad place to work. In this business, never put all of your eggs in one basket (or at least try not to), and never burn any bridges. But all this Avro talk is typical NWA smoke and mirrors. Good luck and perhaps HR will call you to bump you into a CRJ class.