Spoiler ShowOn Master Xehanort's "redemption":
_____Merriam-Websters defines "redemption" as: "serving to offset or compensate for a defect"
With that in mind, I don't think Xehanort did anything to "offset" or "compensate" for all of the atrocities he committed in the name of his personal ambitions. I just think the closure to his arc is more related to the Youngs Eraqus and Xehanort arc.
And to those saying he gave-up, I think the old man got tired. He gave his everything at SDG. He joined with his other selves, summoned the Xblade, and even that could not stop our half-pints.
On to the other Xehanorts:
I don't think anyone got redeemed, but rather Nomura wanted us to feel pity at them.
* Ansem thinking of not carrying forward Xehanort's will, but he outright became indifferent.
* Xemnas then learning the value of his teammates.
If anything, the one that dies a twisted guy was Young Xehanort. I think he represents Master Xehanort's most twisted feelings.
I do think that Luxord was redeemed, seeing as how he gave Sora a Wild Card, and that may have contributed to helping him not die entirely, and transported him to the world we see him in during the Secret Ending.