TCX are still quite strong on routes to places like Egypt, Turkey, Tunisia and to a lesser extent the Greek Isles, Balearics and Canaries from LGW so I wouldn't expect any of those to move anytime soon. However the shorter Spanish/Portugese/Italian routes might get duplicated or shuffled across Larnden to STN if it works for them and they can get a good deal with MAG.
I'm not so sure. Interestingly from Stansted, Thomas Cook are quite strong on the Canaries, Balearics and particularly Greek destinations. Tunisia much less so and noticeably nothing to Cyprus or Egypt. Turkey is the exception as it's significant at both airports.
If anything I'd expect to see something like Cyprus or Egypt from Stansted rather than more Spanish type routes. As Dalaman and Enfidha are the only short/mid-haul routes so far to see increases from Stansted in 2015, that kind of backs that up.