just read that there are going to be several movie length episodes to celebrate the 50th.
Got a link for that? We all previously thought/hoped there would be multiple Specials, but, right now it seems like only the rest of S7, then one Special and then the Christmas Special
I was given to understand two specials- one pre-filmed this spring, and one live episode...
As for Clara, I reckon she's the Bat-Signal, a living meme created as a call (or lure) to a Doctor who's disappeared off the radar post-TWORS. not necessarily by villains.