Ramchal himself agrees that the Great Day of Judgment will occur after the resurrection of the dead, and that everyone will then be judged. Those deserving of punishment (aside what they’d experienced of it in Gehenom) will suffer it then and will be utterly and eternally undone, while those deserving of reward (aside what they’d experienced of it in the Garden of Eden) will enjoy it then .
Everything that had ever occurred in the course of the six millennia of creation will be judged then individually. Then the seventh millennium will begin, when everything will change its form . And then a great rectification will come about on par with what would have occurred had Adam and Eve not erred: all will be pure, all wrongfulness will be undone, and a new and unfathomable world will come about for all of eternity .
And as to Elijah’s role in all of this, as referred to in the quote from Malachi above…
 Ma’amar HaIkkurim.
 Adir Bamarom p. 52.
 Ma’amar HaGeulah.
(c) 2014 Rabbi Yaakov Feldman
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