If i'm not mistaking Roxas was able to use two keyblades because Xion became a part of him(i may be wrong). So if that first statement is true than shouldn't Sora be able to use 3 key blades in 3D? Sense their's Roxas's, Xion's, and Sora's.
By the mission it says DONE in gold letters, but under some of them there are blacked out keyblades under the DONE sign and i have no idea what that means.