Terminals
I would have thought that post development the two terminals need to be viewed as the location where you check-in as opposed to board for some carriers. Pier B will still be there with other nearby stands none of which will be near either the T2 check-in or the T3 check-in.
It's perfectly possible that Jet2 could use T3 check-in but have aircraft on Pier B so it's not a straight forward matter of thinking that if they are T3 based they will be using T3 stands as we know them now (although I've checked in at T3 and boarded on Pier B in the past as it is).