We will see.
A certain Ops Director at Manx airlines adopted a similar approach to yours when they took over a large chunk of Loganair. This was in the days before staff represntation when he declared himself to be a "benevolent dictator". He unilateraly decided to stick all the Logan people below the Manxies and as a result, the vast majority of the Logans sad FU, I'm off. The result - the new company picked up a massive multi million pound trainng bill and a lot of chaos and disruption as they tried to replace all the pilots they thought they would be getting.
I doubt that Flybe managment will be that stupid. Sensible pragmatic negotiations with a bit of give and take all round will be the order of the day if they want it all sorted by April.