Patchwork remarks to Toto that Kansas reminds him of "Bunbury in Septober." Bunbury is a village in Quadling Country and home to the Bun People, many of whom now reside in Emerald City. You can read more about it in L. Frank Baum's book "The Emerald City of Oz."
When Ojo is recounting the plot of the Tin Man comic book, he mentions that Tin Man saved a village of Munchkins from Phanfasms. In Oz, the Phanfasms are a dangerous race of creatures who live on Mount Phantastico. You can read more about them in L. Frank Baum's book "The Emerald City of Oz."
Dorothy and Ojo realize they might be able to harness the power of an eclipse to get back to Oz. Dorothy's great-grandmother often traveled between Kansas and Oz with the aid of natural phenomena, including a tornado and an earthquake.