ok the TLS is non cannon, so it didint even happen. MX is Xehanort, people, how can you not see that. Xehanort is MX's Unversed, so even if MX is gone then his Unversed can still be Xehanort at the same time. Theres nothing that says an Unversed has a Heart body and soul. So i believe that once MX became an unversed he was reborn as Xehanort and lived under Ansem as his apprentice. He succomed to the darkness willingly and since hes an Unversed becoming a Heartless he took Human form as Ansem SOD. And Xemnas is the nobody. Thats why Xemnas calls Aquas armor friend because he was being sarcastic. And why he puts his hand on Roxas's shoulder is because he has no recollection of Ven's face. So basically in a nut shell, MX is Xehanort.
There, I fixed it for you. YOu had a lot of wrongness in there. For instance, you seem to accidentally put that Terra is Xehanort, when SO much more connects Master Xehanort to Xehanort than Terra to Xehanort.