I don’t see how the killer in the latter is a “narrator” just because they have a section or two from their point of view. If you’re taking the term that loosely, what about The Man in the Brown Suit?
There’s a British quiz show (Richard Osman’s House of Games) that has a round almost exactly like this. The only difference is that it’s done in pairs vs pairs, each player answering separately with each pair’s joint answer being the average of their guesses. If you were to Google “Richard Osman’s House of Games Distinctly Average” you’d probably get a good list of quetsions.
The trick is to think of where the answers would come from. You’re looking for government or commercial datasets that are easily available, plus the sort of things that appear in surveys. E.g. the average person will consumer N chocoloate bars in their lifetime, N new motorised tricycles were registered in 2024, the average household will watch N minutes of streaming video in a year etc.
I’m assuming you’ll mainly want to be US centric but some questions about e.g. how many mobile phones are there in India could also be fun.
If you only want the answer to be a number, rather than a quantity, you can add history questions: in what year did Chaucer write the Canterbury Tales, when were teh first traffic lights installed, in what year was Confucius born etc.
Our trivia team had a fallback answer when we were stumped. It was never correct, but we had fun with it. As an example:
Quizmaster: How many dimples are on a golf ball?
Us (puzzled looks all around, then): Bruce Springsteen!
Seriously, I can appreciate what the OP is trying to do, but I think some of the questions in the OP are too obscure for the average person to be able to respond off the top of their head; assuming smartphones and Google are disallowed. If you want numeral-specific answers, make the questions something that the average person would be likely to know, or at least make a decent guess at. Some examples:
- How many keys are there on an ordinary piano? (88.)
- According to the song, what route winds from Chicago to LA? (66.)
- What is MXX divided by X? (CII. Had this one in a crossword puzzle.)
- How many karats are in solid gold? (24.)
- What number did Wayne Gretzky always wear? (99.)
- What number has been retired for all teams in MLB? (42, Jackie Robinson’s.)
Things like that. Otherwise, if you insist on questions such as you posited in the OP, I’d suggest “closest to” either way (i.e. no “without going over”).
How many mobile phones are discarded each day? About 14.5 million.
How long is the longest commercial plane flight in the world? Singapore Airlines Singapore to New York (JFK) route is the longest nonstop flight, covering 9,537 miles in about 18 hours and 50 minutes.
This is the usual rule for most trivia, because just googling the answer isn’t going to impress anyone. But a long time ago, I thought it would be cool to have a round of “Smart phone” questions where it was easy to google the wrong answer, but you could find the correct answer with a bit more thought in how you searched for it.
OK, I guess I’m still not being clear. My bad.
I don’t really want the answers to be known, necessarily. I don’t really want them to be figure-out-able. Just educated-guess-able.
What I want is folks thinking, “dang, that’s an interesting question that I’ve never before pondered. Who the hell knows how many McDonald’s there are in Alaska? My gut is telling me, not that many, so I’m gonna say 5.”
Nobody is going to Google my answer and dispute it. Nobody is going to demand a cite. Nobody is going to question how old my source is.
See:
There ya go, @pulykamell gets it (although there is an element of trivia to it).
mmm
ETA: There are 27 McDonald’s in Alaska. No cite. 
Hmm. I think the Gaia satellite is achieving distances much greater than that, but with increasing error bars the further away the object is. (note that even the 300 light-year distance includes a small error bar). Of course Gaia has a slightly larger baseline (about 2 million km larger than the Earth’s orbit) but that is not particularly significant on these scales.
I’d have to look up the answers for these, but how about:
- How many minutes was the longest tennis match [or pick other sport]?
- How many pieces in a standard Jenga set?
- How many miles is the original Route 66?
- How many items on a Cheesecake Factory menu (unfortunately, I can’t find an exact number for this; they just dropped 13, but the company just says “over 250”)
- How many episodes of the Simpsons has aired?
- How many words in [pick a book: Infinite Jest, Canterbury Tales, Great Gatsby]?
- How many panes of glass on the Louvre pyramid?
- How many ridges on a US quarter?
- How many dots, including power pellets, on a Pac Man board (though this may be dated)
- How many stairs to the top of [pick: Eiffel Tower, Statue of Liberty, Empire State Building]
- How many time zones in Russia
Beauty-full. I will definitely use some of these.
mmm
In case anyone is curious:
How many minutes was the longest tennis match? 665
How many pieces in a standard Jenga set? 54
How many miles is the original Route 66? 2,448
How many episodes of the Simpsons have aired? 790
How many words in Infinite Jest 577,608, The Canterbury Tales 244,338, or The Great Gatsby? 47,094
How many panes of glass on the Louvre pyramid? 673
How many ridges on a US quarter? 119
How many dots, including power pellets, on a Pac Man board? 244
How many stairs to the top of the Eiffel Tower 1,665, Statue of Liberty 354, or the Empire State Building /spoiler]1,57[/spoiler]6?
How many time zones in Russia? 11
I literally heard this one on the radio about a week or so ago, was told the answer, and I still got it wrong!
How many people were predicted to die from fallout from the Hiroshima atomic bomb.
Zero. Fallout was unknown at the time of the bombing. It was only afterwards that it was observed to lead to death.
How many time zones in China? 1
I actually knew the answer to this one, having recently read up on the history of the VW Beetle.
mmm
The game show Card Sharks used guesstimating survey responses, which have a limited answer range. Something like that could work if the “pick any number” kind is too much.
Not entirely true. I went there in the mid-'90s, and they had tours of the staircase. Took the elevator up, then came down the steps with a Park Service ranger as a tour guide. During the construction, various groups donated stones, and had their names, or other designs carved into them. Those carved faces are all placed to face the stairs.
Don’t know if they ever still do those tours. I thought it was great. Was worried it would be full when I went, but it turned out I was the only person there for it.
How many hairs per square inch are on the skin of a sea otter?
I pulled a card at random from Wits and Wagers – I assume one card is Fair Use.
source is in ()
How many slices of pizza does the average American child eat in a year (USDA Farm Service Agency May 2007)
46
What is the minimum age to serve in the US House of Representatives?
25
How many accredited MBA programs are there worldwide? (The Association to Advance Collegiate Schools of Business April 2007)
508
In miles, what is the average distance from the Moon to the Earth (Lunar and Planetary Institute)
238,855
How many times did tennis great Pete Sampras win Wimbledon?
7
How many “spam” emails does the average email user receive annually (TopTenReviews 2006 Spam Statistics) [here the year is VERY important!]
2,200
In what year was Coca Cola first produced (Coca-Cola Corporate Website)
1886
Personally, I would just get a copy of Wits and Wagers and use those questions
Brian
How much wood could a wood chuck chuck? None. Wood chucks don’t chuck wood. 
I beg to differ.
Aha. Jim Lovell went in Apollo 8 and 13. Who were the other two?