Sano actually brought Yamashita onto this episode so it makes sense that their scenes are in tandem. Based off of the looks of things it seems to be...

0:00~0:14 - ??
0:15~0:18 - Yamashita (presumed)
0:19~0:20 - ??
0:21~0:58 - Yamashita (presumed)
0:59~1:01 - Sano (confirmed)
1:02~1:18 - Sano (presumed)

The effects at the beginning are also somewhat Yamashita-esque but sakugawiki mentions nothing about them. Just included them because they look nice and help the scene make a lot more sense.