If Flybe do have the resources and will to set up a base at SOU hopefully it will be much more successful than T3, however if it was a case of putting eggs in baskets I think they should focus more on LM and Emerald.
Logan's MD has stated that they won't open bases outside their core of Scotland and the North and as an island of Ireland-based operation I can't see Emerald doing that either. A mix of those together with a small Flybe base, picking up what Eastern are failing at (flights canx again today) and some of the solid routes operated by their previous incarnation are probably the best (least risk) option for both the airline and the airport.