Is that a Producer-san on the top right?
*edit*
The one with number 2 on her head is Kamaitachi Setsu

Uhh...In the bottom panel...Is that a Firekeeper Friend from Dark Souls 3 on the bottom right side and Jibanyan Friend from Youkai Watch on the bottom, 2nd from the left?

Not enough details in the two to tell for certain. They probably are shout outs, though.

There's the Predator Friend too... this page alone is fantastic!

Nobody seems to have noticed yet, but there's a Xenomorph Friend right next to the Predator Friend. She seems to have a marking resembling the human skull the original version inside its head.