Its actually the other way around. Master Xehanort uses his Keyblade to try and cast out Terra's resisting heart.
Correct, however the Guardian isn't Terra's heart, it's a creature that's holding Terra's heart captive like a prison.
Ansem' and Xemnas' young physical appearance comes from Terra because that's the body Xehanort was using when he created them.
That is incorrect, Terra's heart was always with the Guardian. Ansem the wise's machine did not separate Terra and Xehanort.
Incorrect. Its Xehanort trying to remove Terra's heart. Also the Guardian was already creates at the start of the 2nd phase of the fight.
They established there are multiple ways to get into the Realm of darkness so it isn't completely impossible. Once Aqua fell into that pit of darkness she just sank deeper and deeper and arrived there.
