I stand to be corrected on this, but I believed the plan (B) to be an extension of Stobart Air's franchise agreement with Flybe. Is not the current arrangement basically a wet lease with Sobart being the lessor?.
Surely it will be down to Stobart to determine and provide the aircraft and Flybe to agree their suitability for the routes that they will spend money marketing. I guess there could be some buy & lease-back arrangement with existing Flybe aircraft (other than ATRs) but that would cause so many operation headaches for Stobart I can't see that happening.
ATR's for me. But I would love to be wrong.