- Imperial Astromech C2-B5 was originally supposed to feature in some significant way, as evidenced by his many forms of merchandise. His appearance may have had something to do with droids having or not having personality from frequent memory wipes. He appears to have been a part of the run from the archives to the transmission tower.
SPECULATION: Could C3-B5 been a former companion of K2 that he recognizes, but who doesn’t recognize him? Maybe K2 is able to awaken memories in him to get him to help get the schematics and such.