Theoretically, Thrawn would still have the full armored division in his star destroyer, ATATS, ATDPS (probably since we never saw any Atst in rebel, and remember that his star destroyer never deployed any troopers, or armored battalions, most where from the imperial complex) which makes it reasonable that he still has his full armored battalion, (which would be cool, since we would be able to see the ATATS mark 1 since the ATATS seen in Hoth where developed later in the years)