Theres another cameo of the characters from bear bear .
Pg 20
Actually it's the characters from the one shot: Gendai Mahoutsukai no Okiniiri. Lol
Bear bear is page 10. Right outside the bear shop.
Onee Danshi, Hajimemasu is also page 10
Tzubakisaka Tricolor is page 14.
There's a cameo of Mizutama Honey Boy's characters in http://www.mangago.zone/read-manga/suenaga_yoroshiku_onegaishimasu/uu/d_v-2-chapter-7/pg-17/ (●'◡'●)ﾉ