SquallOfSeed argues about it many times but the answer is a big.
First of all:
Rinoa is Ellone.
Second:
Little Ellone is Rinoa.
Third:
Big Ellone is not Ellone but Junction Machine Ellone (little version).
Odine confounded JME with Elle.(He has lost his creation and donīt recognize it).
Continuing:
X donīt use Junction Machine Ellone but another device to possess Edea (Letīs call it CT).This Device is a junction machine.
This machine sends oneīs consciousness to the past or the future.
X sends to the past (I believe Ultimecia is Edea and she was possessed on a far past).
Odineīs conclusion was wrong.X donīt use his machine.