The CIS Holdouts as a faction is more suited to late Fall of the Republic historical campaigns and the upcoming Galactic Civil War mod, Imperial Reign.

There is no CIS holdout I can think of that still exists and is a bit enough galactic player to be an own faction during the time of TR.
Pretty much all Holdouts were destroyed during the Reconquest of the Rim before the battle of Yavin.

good idea wrong timeframe
if the gcw mod from the teamever happens thats where you can punch the ♥♥♥♥ out of the empire with cis stuff

as it is theres some veeery limited cis units still around

There is a sort of CIS remnant, the something something corporation, they only have CIS troops to my knowledge.

Well, the Rebels annex the left over Holdouts but nothing in the lore says there not around in time and the in-book outbound flight the trade federation had some maps of the unknown regions and wild space so it's possible.

Personally, I would like to see this faction, but probably as submod. A mix of old stuff like: B2 droids, Droid tri-fighter, some old "prototypes/uniques" B3 ultra battle droid, Nimbus Commando Squad and new or upgraded stuff like: Bulwark Mark III, AAT with shield. Most of that stuff is in TR or FotR, so somebody with skill prodoby could kitbash a "New Separatist Union"

Originally posted by Aderod:

Personally, I would like to see this faction, but probably as submod. A mix of old stuff like: B2 droids, Droid tri-fighter, some old "prototypes/uniques" B3 ultra battle droid, Nimbus Commando Squad and new or upgraded stuff like: Bulwark Mark III, AAT with shield. Most of that stuff is in TR or FotR, so somebody with skill prodoby could kitbash a "New Separatist Union"

Try the Legacy of War submod while playing as CSA. Closest you're gonna get to a resurgent CIS at the moment.