I did not read any of the comics. And I am inclined to agree with you regarding it being a different GI after Episode 3. Are the facial markings part of the office, or a characteristic of the inhabitants of the planet the skewered Grand Inquisitor comes from?Different Grand Inquisitor.
If you read the new Darth Vader comics ( which are canon), there has been a few.
I watched the fourth episode today and the bacta tanks do wonders. The old Jedi Master from “The Clone Wars” is back! I guess getting shot at really does focus the mind…