Isaiah says our righteousness is as filthy rags. So who's Ezekiel referring to as "righteous"?
Consider a few other verses from Ezekiel:
But when a righteous man turns away from his righteousness and commits iniquity and does the same abominable things that the wicked man does, shall he live? None of the righteous deeds which he has done shall be remembered; for the treachery of which he is guilty and the sin he has committed, he shall die. (Ezekiel 18:24)
Though I say to the righteous that he shall surely live, yet if he trusts in his righteousness and commits iniquity, none of his righteous deeds shall be remembered; but in the iniquity that he has committed he shall die. (Ezekiel 33:13)
I think Isaiah 64 should be read in this context -- a man/men who have performed righteous deeds, but who have trusted in their righteousness and committed iniquity.
In Ezekiel, then, the righteous man is the man who does righteous deeds and who does not sin -- or who sins, but repents.