On the topic of finding Din's Fire. You are specifically told by the Great Fairy of Power that she has a friend nearby Hyrule Castle "Next time you're in [the Royal Family's] neighborhood, you should drop in on a friend of mine who lives by Hyrule Castle. She'll surely grant you another power." I just feel that unless you were skipping through text and not caring for reading, you shouldn't have missed that. Add on top of that that most players would be curious enough (or wanting more powers!) that they end up searching for it. Frankly I don't see how you could not have found it.
On the topic of finding Din's Fire. You are specifically told by the Great Fairy of Power that she has a friend nearby Hyrule Castle "Next time you're in [the Royal Family's] neighborhood, you should drop in on a friend of mine who lives by Hyrule Castle. She'll surely grant you another power." I just feel that unless you were skipping through text and not caring for reading, you shouldn't have missed that. Add on top of that that most players would be curious enough (or wanting more powers!) that they end up searching for it. Frankly I don't see how you could not have found it.