Corey Olsen didn't sound on board with that, to be fair.
Basically, he stuck to his guns that the Dagor Aglareb was Gothmog's project and Gothmog's armies. He was very opposed to either Morgoth or Sauron being responsible for this battle. He requested that Sauron's forces (werewolves, vampires, cats) not be part of the main battle (though they are able to opportunistically kidnap Annael and Rog while the battle is going on.) And therefore, he wants balrogs to appear in the battle in some capacity, being included in the fighting....and he wants a significant named character whom the audience cares about to die at the hands of the balrogs.
So, yes, with the death of Edhellos serving that function, it's possible to have Angrod wounded rather than mortally wounded. Corey considers her 'important' enough at this point in Season 4 to count as a named balrog death. He can see why the balrogs (especially Gothmog) would go out of their way to smash Sauron's toy (since Edhellos was originally his prisoner, his project).
He did leave the door open for you to try to convince him otherwise, but based on last night's discussion, he sounded very skeptical about having Sauron be the one to kill Edhellos (or appear on this battlefield at all), and very much willing to 'revoke' his pardon of Angrod if she weren't killed by Gothmog.
So, choose wisely....you can only win one of these fights, it looks like.