A German company named Modella used to make dollhouse furniture sets in the 1960s and 1970s that came in little room boxes.
Some were larger than the usual dollhouse scale, the classroom set among them. I have found it a good size for 8" Tiny Betsy McCall which means it is also the right scale for AG Minis.
I found the classroom furniture on German eBay some time ago. Unfortunately, eBay is pretty much the only place to get it these days.
A Modella collector (die puppenstubensammlerin) had scanned the original room box, which had black and white gingham wallpaper, and I changed and enlarged the graphics in Photoshop to make a room box with pale yellow wallpaper for my furniture set.
The teacher is a vintage Miss Ginger doll, Saige and Isabelle are the official minis and Nicki, Lindsey and McKenna are customized from Kirsten (inspired by yours), Ruthie and Nellie. The tiny school utensils are made by Rement.
Nicki is purposely whispering the wrong answer to Isabelle, because that´s just what classmates sometimes do.:)