After some more consideration, I think it makes more sense that an Abandoned quest is not factored into the final Star Grade. The rules specifically state they are discarded and go back into the box.
I like that conclusion. Abandoned is a neutral outcome. And now it occurs to me that if you counted them in to the Star Grade, it would be very difficult for my final score to meet or exceed it if I had any abandoned Quests. Thanks for circling back on this.
In case some else mentions it, the rules also specifically state that a Failed Quest is discarded "back to the box". I still like your conclusion that abandoned quests are essentially neutral outcomes and not factored into the Star Grade.
