I'm proud to have worked on this episode of Studio C! Here's some details on what I did for the shots at the following times in the video:
0:12, 0:37, - tracking, keying, matte painting, and overall compositing in NukeX
2:19 - modeled the mountain and sleigh in Houdini, keying and compositing in NukeX
2:28 - set dressing of the middle-ground in Maya, tracking in Nuke
I finished these shots over the course of a few months.