First, congrats to Carolinus Rex on your promotion!
Second, I think the Kuriles, Ryuukyuu chain, and Pescadores would all be excellent. Maybe they wouldn't be worth much...but like in history: when the Russians start eyeing the nearby rocks for naval bases... the Japanese decide they might actually have value after all!
Also, putting a super weak Showa kingdom on the map would be great... at the least anyone who chose to walk over it would incur BB points from the surrounding nations, and Japan and China could have a CB sheild on them perhaps.
If Bahrain, and all those Carribean Isles can make it... I think a few Pacific ones could as well! I mean during the time covered by EU2, Hawai'i arose into a nation after the introduction of guns... perhaps that is a good idea.... after trading posts are established the chances for an Iroquois-strength type nation could arise! That way, selling guns to the natives would not be without consequence...and would make settling the American West more realistic as well.... the Native American raising up armies that campaigned around, instead of waiting to be slaughtered!