In a later story, actually the first chapter of her book King Kojo, Thompson reintroduces the Ogre of Oh-Go-Wan. But is this the same ogre, or a different one? Since the ogre in that story dissolves in salt water, it's unlikely that he would have lived on an island in the ocean. There's no reason why Og couldn't have also lived in Kojo's Kingdom of Oh-Go-Wan at one point, though. While he identifies himself as the Ogre of Ogowon, there's no indication that this is the name of the island where he lives, and a flag calls it Mount Up. So perhaps there's a connection between the ogres, but they're probably two different characters.
I'm also going to address trolls in Oz, but I don't believe there are any in the Famous Forty. Canonical authors Eloise and Lauren McGraw do, however, introduce a troll in their Forbidden Fountain. He's a Toll Troll, who lives at a bridge and demands that anyone crossing it pay him in honey. Trolls are also quite significant to the plot of Eric Shanower's graphic novel Forgotten Forest. His trolls, who dwell in a volcano near the Forest of Burzee, are nasty, but hardly ogrish brutes. In fact, they're notorious schemers, with their king having a long-term plan to seduce a wood-nymph named Nelanthe and use her to help destroy Burzee.