Any reason the organization members rearrange their names and add an x? I mean does it have to do with the x-blade from birth by sleep? Sorry if this has already asked this but I'm just wondering.

It was Xemnas' idea because of his memories of the X-Blade, yes.

that plus its badass

It's an Xcellent letter.

 

It was corny, but please laugh.

 

Xemnas remembered being obsessed with the X-blade as a somebody, so he let this feeling drive him.

It's to do with the X blade yes. I think that it was something like the letter X became special to him, so when creating Organization thirteen and renaming the nobodies, he added Xs to their names.

Xemnas considered every memory of his original self (MX) important, so he'd always look for ways to remind himself of stuff. Like how MX used to wear a black coat, and is how that's now the Org's standard outfit. And the X-blade, which MX seemed to emphasize on the "X", even explaining it's origin, was also given to the Org. That's just my theory, at least

And they wanted everyone's names to sound horrible in Japanese since their language doesn't have an 'X'. Akuseru, Rokusasu, Zekushion, Demikkusu... I could go on and on Though none of this is as bad as Ven's name pronounced 'Ben' because they can't pronounce the 'v' sound.

So, this whole time we've been pronouncing their names wrong. It's actually Key-Em-ness, Ro-key-ass Key-on, Ack-key-el

Etc.

Otherwise Ro-kye-ass, etc. But I digress.