Tagged the remaining four people:

• cap and glasses in the middle, possibly Kumazaki Shinya
• brown-haired in the bottom left, possibly Ohara Megumi
• pink-haired with glasses on the bottom, almost definitely Ogasawara Yuuta
• grey-haired with glasses, probably Sakai Shogo

This follows the pattern of those who gave commentary in the festival, and the first four featured in this promotional video.

The one I'm least confident on is Kumazaki, as I didn't see him wearing a cap in any images or that video. I couldn't find footage of the concert's commentary from some quick searches, so I'm guessing he wore it in the festival.