[Kyttias]

I think this is all:

UPDATE `adopts_friend_requests` SET `fromuser` = "NEW_USERNAME_HERE" WHERE `fromuser` = "OLD_USERNAME_HERE";
UPDATE `adopts_friend_requests` SET `touser` = "NEW_USERNAME_HERE" WHERE `touser` = "OLD_USERNAME_HERE";

UPDATE `adopts_inventory` SET `owner` = "NEW_USERNAME_HERE" WHERE `owner` = "OLD_USERNAME_HERE";

UPDATE `adopts_messages` SET `fromuser` = "NEW_USERNAME_HERE" WHERE `fromuser` = "OLD_USERNAME_HERE";
UPDATE `adopts_messages` SET `touser` = "NEW_USERNAME_HERE" WHERE `touser` = "OLD_USERNAME_HERE";

UPDATE `adopts_online` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";
UPDATE `adopts_owned_adoptables` SET `owner` = "NEW_USERNAME_HERE" WHERE `owner` = "OLD_USERNAME_HERE";

UPDATE `adopts_trade` SET `sender` = "NEW_USERNAME_HERE" WHERE `sender` = "OLD_USERNAME_HERE";
UPDATE `adopts_trade` SET `recipient` = "NEW_USERNAME_HERE" WHERE `recipient` = "OLD_USERNAME_HERE";

UPDATE `adopts_users` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";
UPDATE `adopts_users_contacts` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";
UPDATE `adopts_users_options` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";
UPDATE `adopts_users_profile` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";
UPDATE `adopts_users_status` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";

UPDATE `adopts_visitor_messages` SET `fromuser` = "NEW_USERNAME_HERE" WHERE `fromuser` = "OLD_USERNAME_HERE";
UPDATE `adopts_visitor_messages` SET `touser` = "NEW_USERNAME_HERE" WHERE `touser` = "OLD_USERNAME_HERE";

UPDATE `adopts_vote_voters` SET `username` = "NEW_USERNAME_HERE" WHERE `username` = "OLD_USERNAME_HERE";

HoF, could you double check that we aren't missing any?

This doesn't cover forum stuff, however.