Question as stated. Dark Acolytes refer to any non-Sith dark siders Palpatine and Vader trained to execute the Great Jedi Purge. Unless the future events of Rebels lead to the destruction of their organisation, the Rebellion will otherwise have no means of destroying them all, since they lacked Jedi to counter Inquisitors and the like with (Luke did not pursue proper training until Dagobah). Are any of them still alive by the time of the Galactic Concordance or later, when the New Republic formally took control of the galaxy? There's no known indication they founded the Knights of Ren.