I'm not sure specifically what 'Cap deage' means. It could be a very specific term, a misspelling, or something relatively unknown. It might be a proper name, a local term in a certain area or a very niche concept.
The cap man and monkey story is an interesting one. There was this cap man who was traveling around selling his caps. He reached a place near a forest and decided to take a rest under a tree. While he was sleeping, the monkeys in the tree noticed the caps. They climbed down, grabbed the caps, and went back up the tree. When the man woke up, he was confused at first, then saw the monkeys with his caps. He was worried as those caps were his livelihood. But then he remembered that monkeys often mimic human actions. So he took off his own cap and tossed it. The monkeys, being the imitators they are, did the same with the caps they had taken, and the cap man got his caps back.
The 'A Cap for Steve' short story could be analyzed in terms of its themes, like friendship or self-discovery. The characters' development and their interactions might also be key points for analysis.
The cap in 'A Silent Voice' manga might symbolize something related to a character's identity or a specific event. It could add to the visual storytelling.
The Christmas story stocking cap can be a symbol of the holiday spirit and add a festive touch. It might bring back memories or be a part of traditional Christmas outfits.
I really don't know. The author might not have made it clear or there could be mixed signals. You might have to analyze the context to determine Hugh's feelings about the cap.