Question: Which original stories were the archival shots that Clara was retconned into taken from? The only one I know for sure is Pertwee Driving Bessie in "The Five Doctors".
First Doctor: Not sure.
Second Doctor: The Five Doctors.
Fourth Doctor: The Invasion of Time
Fifth Doctor: I'm not sure but I want to say either Four to Doomsday
or Resurrection of the Daleks.
Seventh Doctor: Dragonfire.
First- The Aztecs, though his line is from The Web Planet
Second- The Five Doctors
Third- The Five Doctors
Fourth- Invasion Of Time
Fifth- Arc Of Infinity
Sixth- none, it was an extra wearing the costume
Eightth- None, it was an extra wearing the costume
Ninth- None, it was an extra wearing the costume
Tenth- Silence In The Library
1) I thought the line at the start was actually from the first episode (when he finds Ian and Barbara hiding in the junkyard), though the visuals may be from somewhere else, and isn't the surveillance cam shot of the Doctor and Susan entering the TARDIS from The Daleks (with a lot of CGI repainting of the actual set around them), when they're infiltrating the Dalek city? Haven't double checked though... Then there's that shot The Aztecs in the 'Dying a thousand times montage.
2) Similarly, there's a 1960s shot of Troughton in that montage, along with a Yeti from Web of Fear 1. Very familiar, he's working on an oscilloscope that's just offscreen, I think, so it might be Wheel in Space or Ice Warriors.