In the cartoon, Storm Shadow and Bludd were field commanders, but didn't seem particularly high on the chain of command, while Destro and Zartan did contracted work with Cobra. But Destro was in nearly every episode CC was in, acting essentially his primary advisor, so. . .I don't know. Seems like Destro's role shifted over time to the point where he was more officially a part of Cobra than in the early stuff. Pre-1986, apart from Cobra Commander, the Crimson Twins and Baroness were the only ones that seemed explicitly high up in the official chain of Cobra command. Firefly only rarely appeared in the cartoon, as did Scrap Iron, so I wouldn't rank either of those guys very highly.
Mindbender appeared in the same episode Serpentor did, so if you say he is high in the ranks then I guess you have to say the same for Serpentor (personally, I try to pretend both never existed).
