A Mistake Worth its Weight in Gold

[Alpha Dude]

eating half an apple from an orchard full of fruit bearing trees while one is so hungry so as to not even realize it was someone's property/provision falls under the rule of extreme necessity allowing-some of-that which is forbidden.

This is true. However, you're not taking into account the extreme taqwa the salaf had. They wouldn't have wanted to transgress even on mubah/permissible but doubtful matters. So no, it's not far from reality that he would have felt bad for eating something that did not belong to him.

and marrying off his blind, deaf And dumb daughter to the first guy who eats half an apple form his garden hardly seems to be setting a good example

No, once again, it's not just any random first guy who ate half an apple, it's a guy who displayed extreme taqwa. At those times, people actually valued it more than they did wordly things like wealth. So in that context, I don't think it's all that unbelievable that a father who had concern for his daughter's hearafter would marry her to a pious man.