"Alos, Graham is the only one I've seen use the mirror, and you still need a king, no matter what magic you have."
Actually Prime Minister, or even Captain of the Guard, or the generals can take command if king is incapacitated. These characters are mentioned in the manuals, among other sources.
You probably havne't played King's Quest 4, or King's Quest 6? Because other people other than Graham use the mirror, Rosella and Alexander. Infact the mirror will work for anyone wants to use. Edward once used for example, before he lost it.
Besides, saving their lives doesn't justify every action he may or may not have taken.
He never murdered anyone, he only defended himself, from enemies that attacked him first. He also only took a tiny bit of gold and promised he would return it and avenge them. I see nothing wrong with that. Besides if he didn't take the gold it wouldn't have served anyone any good. As statues they were dead, and the dead do not need gold.
Hell Graham, Rosella, Valanice, and even Alexander hav stolen more on their journies, than he did on his single journey. Not to mention they also broke or entered into homes that were not theirs to enter without permission. They are no different.
" That is 1:in the spinoff lioterature, which I don't view necessarily canon to KIng's QUest."
Ok ignoring the novels which is your prerogative, even though they are infact official, and are a secondary source of canon.
Actually the Guidebook to the Land of the Green Isles is part of King's Quest 6, and is its manual. It is infact very much canon same level of canon, and needed to beat King's Quest 6. There are also refrences in the official games if you know where to look as well, that point out average life span is same as on earth for regular people (unless of course you have some magical way of staying alive longer than usual). Hell the games actually implied that the stories take place on earth sometime in the past.
Yes I agree because graham ate the fruit he may live longer than most people. But that will make him above average.