The word balloons are covering the sign, but the building in the background of the first panel is the Ozian Museum of History and Art. It's not important to the story nor is it a reference to anything. I just thought Emerald City would definitely have a museum on Banana Blvd.
I based the lamp posts on the art from one of the covers of Emerald City of Oz. I stole one of the buildings in panel 6 from Dick Martin's Cut & Assemble Emerald City of Oz, which is out-of-print but very affordable on the used book market.
One of my favorite minor characters is on this page.
Footnote: I've mentioned the crystal balls before.