Originally, an island known as Shipwreck Cove (designed by producer Jason Kim) was going to appear in the game, with much of its data remaining in the game files. Despite how finished the remaining materials look, designer Brian Kaiser claimed that the developers did not get very far into production on it. The full level layout can be found in the unused data, meaning that the island can be stitched together using several models. Four NPCs were intended to appear on the island, those being Vice Admiral Morgan, Neema, Theodore, and Mira (who would later be reworked into Mira Cull, the daughter of series regular Barney Cull in MySims SkyHeroes; it's unknown if she was intended to be related to him in this game). Additionally, five music tracks related to the island are also in the game files, the names of which suggest that planned landmarks for the island include a Pirate Lighthouse, Mira's House, and Neema's Shack.

On the cover of both versions of MySims Kingdom, King Roland is depicted as having light blue eyes. While this is reflected in the Wii version, the DS version instead depicts him with grey eyes in-game.