The last time I looked the FAA had 28 fully qualified pilots, plus others in training. The Italians and Spanish seem to get by with a lot less.
Their has always been a migration officers to/from the RAF and the FAA. When the F4 was withdrawn, I gather all aircrew were given the opportunity of joining the RAF and I believe there were some takers.
Of course, we have no idea what is going to be announced, but I would expect that they would have looked at making the Harrier force exclusively maritime focussed, enabling them to cut a squadron.
Just my 2p.