Uh...hello people, I'm new to these parts and I couldn't think of a better way to introduce myself than to give you all an idea of whats been going through my head while I wait for KH3 to come out. Bare with me, some of my facts may be twisted, as some of these things are based off from what I remember reading about. I hope this opens up great discussion and hopefully I'll be accepted into this community This topic has possible spoilers for KH3D and BBS for those that haven't played them.
How long does this process take?
While we have no certain time frames, there's one reference point we as a community can use. We first see Braig in Radiant Garden after Terra departs from his two friends. Braig is shown later to be in cahoots with Master Xehanort for reasons we already know why. The first time we see him, he is a "normal" villain with his own unique powers.
Kingdom Hearts Birth by Sleep - Terra vs Braig [spoilers] - YouTube
Now in Aqua's story, she's faced against Braig, but this time he's different. He's opened his heart to darkness, but more importantly, he's been Norted. With the yellow eyes and pointed ears, our simple villain has turned into a major plot advancement and a future seeker of darkness. From the time of Radiant Garden to the near final battle in the Badlands, anytime between then, our friend Braig has been seeded. Could willfully being seeded affect the process at which it progresses? Maybe, I can't say. It's safe to say, at minimum, it does not take long for the affects to start showing.
Kingdom Hearts: BBS - Braig (Xigbar) (Final Boss, Aqua's Story) *No Damage/CM* - YouTube
Who is actually capable of doing the seeding?
This ability to essentially "seed" someone's heart means you'd have to first, to my understanding, extract a piece of your heart, and implant it into another. Those that have the ability to extract hearts are KeyBlade Bearers as is written in Xehanorts 9th Report.
Report 9 We keyblade wielders have special abilities. We are able to extract hearts from ourselves, or others. If I were to repeat this process, it would be possible to exist in this world for eternity.
When I was a boy, at the edge of a world I saw in a dream, I arrived at a world that no one else had ever seen. I opened the door to Kingdom Hearts, creating a new world, with light and darkness in balance. With this new knowledge, a new objective for me was born, but what I was left with was this old body. The next thing to do was to look for a new vessel (body/container). Then I met Ventus, and made him my pupil. Meeting him was destiny. I sensed his nature, but he was too kind hearted. I decided that Ventus’ fragilty made him unusable as a vessel, so I will use him for my other plan instead. I will remove the darkness from Ventus’s heart, splitting him in two. This will result in a heart of pure light and a heart of pure darkness.
It seems as though you need to be Xehanort himself to essentially nort someone right? So he only had a certain amount of time to do so.
Xehanort had decided to implant 13 different vessels with his own heart, but surely he wasn't alive to be able to Nort all of Org 13 before he made himself a heartless/nobody right? If so, who could he have norted? From his time as Master Xehanort to Apprentice Xehanort, I'll explain my reasons for who could've been norted, and how.
Who could've been seeded? How?
The original 6 members of Org 13 were the prime variables to be included into the final 13 Seekers. Why? Because that's who were there from the start. Braig, Ienzo, Dilan, Even, Aeulos(sorry lol) , and AX himself were supposed to be at least half of the Org. Xehanort could not have seeded someone else afterwards, because he himself, had gave up his heart to make Ansem and Xemnas.
So I say this, those that could've been seeded by his own hand, had to have been the ones I've named this far. Why do I think that? Because he was the only wielder there...at that time.
The remaining 7 members, he could not have seeded, because they were found after the Org was formed. You might be asking, "Then who could've seeded Isa since Xehanort was no more? Isa had to have been there along with everyone else right?"
Not in this case.
Kingdom Hearts Dream Drop Distance Cutscene My Name Is Ansem - YouTube
We know Isa and Lea joined the organization at the same time, so wouldn't they have woken up together at the same place? Wouldn't they have both been struck down at the same place? Lea wakes up in that room where Ienzo and Even were struck down, so why don't we see Isa and Lea there? It's because someone other than Xehanort extracted there hearts. Someone else with a Keyblade. Who then? Who else could have extracted, or, seeded Xehanorts Heart seed into Isa? This, I believe, was done by none other than Xemnas.
On a side note, let's not forget we still have unstable people, which could mean the seed could be interfering with the somebody returning. Perhaps they weren't picked up in time, who knows, but that would prove my theory correct that they could've been seeded when they got their hearts extracted.
Not only does this halfed ass analysis of mine help me organize my thoughts, it also theorizes that Xemnas could indeed Wield a Keyblade. He didn't show it, because it would've shown the members that they found indeed grown hearts of there own.
There are many holes in my analysis/theories like the time Isa actually joined and how long it took for him to be seeded. Thank you if you took the time to read this, it's the only thing I could think of doing to keep the community talking and things fresh until KH3 news starts pouring out.