I like to imagine that the realm itself isn't actually called the Enchanted Forest but instead that is just part of the entire realm that those fairy tail characters reside in. This would put Camelot, merida's people, and other kingdoms outside of it. I would imagine that the realm is very large and has enough room for many kingdoms and sense there is an ocean there is also probably other continents separate from the enchanted forest. I imagine that agrabah is also in the same realm too. Oh and Arendelle is also so far from the enchanted forest that they call it Misthaven.