A Fragmented Plan

[Veritas7340]

I've never played DDD b/c I don't own a 3DS. (only owned and beaten KH, CoM, KHII, BBS, Re:CoM)

However, from what I gathered from Youtube videos of the important scenes -- Xehanort's true plan is to have 7 Pieces of Light and 13 Pieces of Darkness to clash to form the true X-Blade.

When Apprentice Xehanort became Ansem SoD and Xemnas, can it officially be said that this plan was fragmented between the two?

Ansem SoD, via manipulating Maleficent, gathered the 7 Princesses of Heart, 7 Pieces of Light.

Xemnas, via assembling Organization XIII, gathered 13 Members, 13 Pieces of Darkness.

Moreover, in KHI Final Mix, it is conveyed that Xemnas was surveying Sora's activities. If he knew what Ansem SoD was doing, could he have brought Organization XIII to meet up with the captured Princesses of Heart?

 

[Gram]

That is indeed what the plan seemed to be in a nutshell. Ansem and Xemnas essentially took MX's plan and divided it in half, each taking a role.

No not yet, before Xemnas could use the 7 pure lights found by Ansem he first had to fill 13 empty vessels with darkness which is what he formed the org for.
As pointed out by Xigbar in DDD, Xemnas' plan was to gather empty husks and hook them up to his false kingdom hearts and from there fill them all with the same mind and heart.

 

[Ruran]

The way I take it, it's more like Xehanort had a bunch of contingency plans. It's presumed that the "true" way to reach Kingdom Heart (form X-Blade via gathering seven lights and thirteen darknesses and make them clash) is the most difficult, so he tried finding other ways, while gathering the necessary components to do things the right way if need be. Making a someone with a heart of pure light clash to form the X-Blade, using the Heartless to create "The Kingdom Hearts of Worlds' Hearts'" and gathering the PoH, and using the Nobodies/Org. 13 to create "The Kingdom Hearts of Peoples' Heart's" were all failed "shortcuts" that were made for efficiency, but worked to find what Xehanort needed anyway.

 

[Veritas7340]

So only darkness from the false Kingdom Hearts would do? But in DDD, Xehanort was going to fill Sora with his darkness without the aid of that Kingdom Hearts....

EDIT: It's weird b/c I agree with you both, Anagram and Ruran.

On one hand, I can definitely see Apprentice Xehanort's memory of the Kingdom Hearts plan being fragmented into both his Heartless and his Nobody.

On the other hand, I can also see the contingencies short-cut plans being an explanation too, seeing how it would corroborate Xehanort's line to Terra in BBS when he says something along the lines of: "having many different plans" or something like that

 

[Gram]

So only darkness from the false Kingdom Hearts would do? But in DDD, Xehanort was going to fill Sora with his darkness without the aid of that Kingdom Hearts....

As Ruran pointed out it was all contingency. The plans of Ansem and Xemnas failed but found MX what he needed for his x-blade plan.
And no that is wrong, Xemnas was simply planning to use the false kh as a means to make all the org members into Xehanort, it's not that he had to use it it's just that was the means he was planning to use.

MX on the other hand can use his keyblade to make vessels. Same plan different means.