Flybe have opted for T3, which, don't forget, will be connected to T2 by both airside and landslide links, so, transfers should not be an issue (even if there is a slight walk).
That makes sense - providing there are efficient moving walkways which are switched on nearly all the time - but it would make fitting Jet2 into T3 more difficult even allowing for AA, AF and KLM moving out. In any case, all of this is several years away, and who knows what changes there may have been to airlines, their operations and their ownership in the meantime.
As an aside, good to see the 4 x VS flights on the T2 departure screens this morning, along with DL, UA, CX (very busy again by the looks of it) and SV.