These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
This is not so much a Take That aimed at Queen as it is a joke about the ubiquitous nature of Queen'sGreatest Hits I in car stereos throughout the UK. Terry Pratchett explained it like this: eventually you get so sick of inane local radio that you pull off the motorway and go to a service (gas) station to find something worth listening to. The only thing on the paltry rack of cassettes that is at all worth buying is invariably The Best Of Queen. (There are doubtless several things that are outdated with this scenario - CD changers, iPods, better radio stations, better stocked service stations - but it was brilliant for its time.)
Fan True Name: Crowley's 'angelic' name is never given, but Kireawel or Caphriel is popular in fanfiction.
Also Gadriel, as it is listed in some theology books as being the name of the fallen who tempted Eve with the apple.
Genius Bonus / Punny Name: The etymology of "nice" (or "niƒe" if you prefer) has changed drastically over the centuries. Roughly around the time Agnes would have written her book it could indeed have meant "precise". However it's original meaning was "foolish" or "stupid." Then there is the modern meaning attached to the word. They all apply to some extent.
As Lucifer, in Latin, means "light-bearer" or "bringer of light", Pulsifer can be translated as "bringer of peas". However, the authors have noted that this wasn't planned, but was merely a fortuitous coincidence.
There is a particularly ship-worthy line towards the end of the book: "And perhaps the recent exertions had had some fallout on the nature of reality because, while they were eating, for the first time ever, a nightingale sang in Berkeley Square." The line comes rather out of nowhere and nothing is specified about the nature of said "exertions". One would assume it refers to Adam remaking reality, but "A Nightingale Sang in Berkeley Square" is an old and sappy romantic love song, whereas Adam is pretty clearly still at the cooties stage. The scene also takes place smack in between two scenes featuring canon couples that confirm the continuation/beginning of their own relationships.
"There were angels dining at the Ritz" - from the song in question. Aziraphale and Crowley dine at the Ritz regularly. The mention of that song is probably not for the sole purpose of creating Aziraphale and Crowley subtext- though one of its purposes could be that subtext. That one is unsure if it's a dream or reality most likely refers to the characters forgetting, and a couple of other lines apply well to the book, more like.
Heterosexual Life-Partners: Aziraphale & Crowley, 6000 years or so worth of life partnership. Though 'heterosexual' is a bit inaccurate, since neither technically have a gender unless they really want to make the effort.