I am not sure that anyone really knows the disposal yet of the various GB aircraft. Nonetheless, it is clear that the new 'easyJet Gatwick' will be a large beast which is bigger than many airlines. 35 aircraft, going to wherever they finally end up is a big outfit and all pilots should be happy at this deal.
I note that some people at GB are concerned they will somehow be earning less as easyJet employees. It is simply not correct and it is only when you become an 11-year captain that you start earning more (and that includes all pension contributions and medical benefits).
Regarding 'seniority', it does not exist at easyJet in the same way it does at GB. There is an understandable concern that everyone will be shoved on the same 'year 1' salary. There will no doubt be some discussions, but such insensitivity would be a recipe for industrial unrest on a grand scale. It is inconceivable to me that easyJet will not just assume a date of joining going back to the date of joining GB (or at least dating back to the start of easyJet!) for salary purposes. That only affects 'loyalty bonuses' (5%, 10%, 15% of basic after completion of 2, 5 and 10 years' service) paid net annually on the anniversary of joining. I would hope that would be taken as a given. Other less clear areas would be the dreaded car parking 'base seniority' system in operation and place on the list should subsequent redundancies ever occur. Like all these things, there will be winners and losers but there is nothing that cannot be dealt with to everyone's mutual satisfaction if a sensible approach is taken.
There is no reason for any GB pilot to be anything else other than very happy to be part of easyJet, despite the inevitable changes that must occur. As these things go, this is a great outcome for all concerned and we genuinely look forward to working for the first time (or in my case the second time!) with our new colleagues. Come on down - you'll love it!