Nancy Drew and the Hardy Boys are both famous children's detective stories.

I thought Brown was Father Brown, a priest who assists detectives in a TV show, in a fashion similar to shows like Castle, Murder She Wrote, and Diagnosis Murder, where police can't do their job so they get non-police to do it for them. (Or Psyche, for a comedic take on the genre.) But that is definitely not kid's lit, so I dunno what it's about.

As for beds...canopy is another name for a 4-poster bed. A Murphy bed is a fold-down bed, often seen in studio apartments. A day bed is one I didn't believe even after Googling it (the other two...I at least vaguely recalled it once I heard the category, but I didn't work it out myself). Seems like a day bed is basically a variation of a lounge that's a bit more designed for sleeping on than a regular lounge.