A new version is a new version. He is essentially making covers of Soul Coughing songs.
If they were remixes, he would have used the original source tracks from Soul Coughing and turned them into new tracks.
If he would have remastered the tracks, he would have taken the original source tracks and then would have mixed/mastered them differently.
You cant call something a remix if you just arrange a song differently, and do not use any of the original elements.
And that is what i think the difference is.
(not that wiki is the last word but it mentions this in the entry for remix)
http://en.wikipedia.org/wiki/RemixRemixes should not be confused with edits, which usually involve shortening a final stereo master for marketing or broadcasting purposes. Another distinction should be made between a remix and a cover. A remix song recombines audio pieces from a recording to create an altered version of the song. A cover is a recording of a song that was previously recorded by someone else.