Neither Wideroe nor Emerald (at this stage) have a UK Operating Licence and AOC, so neither has the traffic rights to fly domestically within the UK. They'd be ruled out of bidding for the PSO on that basis alone.
Flybe with a Q400 has to be fanciful at best.
Unless Airtask have come up with something - and it's difficult to see what - then it looks like a straight Eastern J41 v Loganair 340 contest is the most likely.