Right now, according to the TOR Encyclopedia and the game. These council members are still alive.
Sphere of Ancient Knowledge: Darth Nox
Sphere of Defense of the Empire: Darth Marr
Sphere of Expansion and Diplomacy: Darth Ravage
Sphere of Imperial Intelligence: Darth Jadus/Zhorrid
Sphere of Laws and Justice: Darth Mortis
Sphere of Mysteries: Darth Rectis
Sphere of Production and Logistics: Darth Vowrawn
Sphere of Sith Philosophy: Darth Aruk
Sphere of Technology : Former Councilor-Darth Mehkis- Darth Hadra-Darth Karrid
Gravus was a good choice but
. Actually nobody fit better than Mehkis.
Sphere of Military Offense: Former Councilor-Darth Vengen-Darth Baras-possibly Darth Arho
I guess Darth Tormen is perfect for this sphere, he's a bit overly ruthless but is also very tough.
Sphere of Military Strategy: Former Councilor Darth Decimus.
I guess Darth Charnus will mostly succeed on this sphere.
Sphere of Biotic Science: Former Councilor Darth Acharon
Maybe Darth Viktus?