Just gonna note here that it’s not canon that X split in pieces and it’s mentioned nowhere at all officially. It’s purely fan conjecture and has been going around again and again on the megaman wikia.
The Guardians were all built, and their original purpose was world restoration (except Phantom, who was charged with guarding X).
Oops. Well, that’s what I get for trusting the wiki. I think the Copy Ability synthesis theory is cool though. Hmm well if that’s the case, my original theory of Robot Masters surviving through to become the Guardians is still technically plausible, although their loyalty to X would have to be explained some other way. Thanks for correcting me there, I assumed it was mentioned in an art book or Complete Works or a soundtrack or something.
Well if nothing else the design similarities from series to series have been noted in my posts, which was my original intention. I stitched the fanon on as well to hold it together better.