I'll answer your questions

Is the fourth key the Key of Enraged Monkeys?

No. No even a little.

If no conscious preparation will adequately prepare us, are we best equipped by preparing for no real thing in particular?

Alternatively, is this one of those "the journey is more important than the destination" dealies?

To what higher authority might I beseech the confiscation of Fogel's key, so I might later gain it for my own mostly-benevolent ends?

You will be best equipped by seeking actual equipment. Garner her favor. She watches. She will give the devoted the tools they might use to succeed. The Advanced Question Larder and the "power" "tool" are such weapons. The contents of the Master Chest... may be the most powerful of all.

You can beseech any higher authority. Ask goblin's

In a post-scarcity society where everyone was encouraged to spend their lifetime advancing knowledge in one particular thing, what would you specialise in?

The understanding of animal behavior, specifically the components and mechanisms of crow communication and community.

Or parasitology.

In a post-scarcity society where everyone was encouraged to spend their lifetime salvaging bacon, what type of salted meat would you prefer? This is a very important question, integral to your survival.

Bacon. When gold is gold, go for the gold.