easyjet_A321 - welcome along.
I would make an educated guess that Monarch would be the A321 customers - they seem to be the only people buying them these days, although as they will be fresh off of the blocks they may get sent anywhere! But my interprtation is that is it a done deal.
MAN is up in the air at the moment. It is certain that there will be expansion at the airport but it may differ from their origional plans as other factors such as LTN and the recession have made changes to their plans. I would like to think that as they reduce frequency at LTN, they move some more up north to MAN. They origionally planned to have 5 aircraft at MAN by 2010 and double that at LPL down the road but I don't see that happening somehow, the latter that is.
As I say, all up in the air and now a days, its when the aircraft actually touches down at MAN that we can be sure the services start.