Ahhhh, there's the (high) possibility that messing around with the flags might enfucken things in your save, especially since there's a zillion or so variables related to Arona and the orcs. It's hard to know exactly what you'd need to change to get the outcome you want (since I can't read your mind and know what you did the first time or what you consider 'good') but at minimum you'd need to change the flags that cover the completion of the quest. You'd want to remove ORC_QUEST_DESTROYED if you see it and you'd probably need to alter the value of ORC_QUEST_COMPLETED; based on some quick testing a value of 1 there records Chieftain!Arona so removing the former flag if you have it and flipping the latter's value from negative to positive might do it.
Caveat: My runs always resolved with Arona on the throne so I don't have multiple states to compare (just some quick and dirty testing with an old save) and whatever you do, you'll ruin your file for bug reporting purposes and might run into unexpected errors down the line even if nothing breaks immediately. Just warning you.