Thanks for starting this post. The 10 essential questions is a good start. I don't bring a knife on almost any hike, but the other ones usually make it. I guess my inclination would be to look at what I personally do before planning a hike:
1.) What resources did you use to plan the hike (AMC WMG Edition: ##, Other Guide Books, Websites, Relying on other people in the party, etc)
Reason for question: Knowing what to expect is important. If you read the guide, you'll have a great idea what to expect on the trail. If you read trail reports, then you'll likely be aware of current trail conditions.
How to score: 1 = No resources used; 2 = At least one; 3 = Two or more
2.) Was this your first time in this specific section of trail?
Reason for question: Experience is important. While asking 'How experienced of a hiker are you' is fairly subjective, if someone has been on a specific trail is a great way to assess if they knew what they were getting into.
How to score: 1 = No; 3= Yes
3.) Did you let other people know about your plans?
Reason for question: If you go missing and people don't know where you were planning to go, it makes the search much more difficult. Perhaps this question only makes sense to ask if there was a search involved?
How to score: 1 = No; 2= n/a; 3 = Yes
4.) What did you do to prepare for the weather?
Reason for question: The forecast is a major part of every hike. Even if weather isn't an obvious factor, checking the forecast and being prepared for the conditions is a great indicator of preparedness. Chance of precip, wind, and temperature should be on everyone's mind while planning a hike.
How to score: 1 = Nothing; 2 = Checked long term forecast/checked regional news station/paper; 3 = Checked local forecast (internet)/radio
5.) What were your bailout options?
Reason for question: Knowing your options (or when to turn around) is important to making it out safely. Comparing a road walk vs extra trail miles; saving miles but adding vertical; taking a longer route down a more gentle trail; taking a short bushwhack to avoid a dangerous crossing, etc.
How to score: 1 = None; 2 = Turn around but too late; 3 = List of bailout options
6.) What is your physical condition relative to the hike demands?
Reason for question: Someone who is out of shape (read as not in good hiking condition) will have a harder time with the terrain. Biting off more than one can chew, getting tired on the way up and then going very slow on the way down, etc. Lots of ways that conditioning plays into a hike turning into a S&R. Everyone has their own limits, but I feel as though most people can reasonable judge the limits of others based on their appearance and behavior after a short bit of rest. Perhaps the best way to think about it is the 'type of fun' they had.
How to score: 1= Clearly exceeded physical limits (type 3 fun); 2 = Pushing their limits (type 2 fun); 3 = Within their limits (type 1 fun)
7.) If injured, did a lack of gear or experience lead to the injury?
Reason for question: Injuries happen. People take a wrong step, a rock slides, etc. Improper footwear is preventable though, an with experience people learn what routes to take in different weather, and what gear to bring
How to score: 1 = Yes (Improper gear directly lead to accident) 2 = Had gear but wasn't using it properly/at all; 3 = No, this was reasonably unavoidable (includes 'dumb' things like 'I tripped over a railroad tie').
I like most of these but conditioning is relevant to your plans. I'm quite a bit overweight these days but I know I'm not up to a Pemi-loop or one day P-traverse. However, for a guy my size, the legs are used to your average day hike.
The lawyer card is sadly, a decent idea.
I'd want to know what their plans were and what time they had planned on starting Vs. what time they actually started. If they started late, was changing their plans an option. Now I enjoy a beer or two when I meet friends the day before a hike also; but when you plan a five or six o'clock start and have too many that you have a 9:00 or later start, your four hours late. The choir here carries two or three lights. If you planned a sunrise to almost sunset hike & forgot headlamps & then started late & thought, we'll hike faster, that's a poor plan.
Several rescue tales have started, "we got a late start" while not always the case, sometimes it's not hard to see they were up too late the night before. (If you were just stuck in traffic for hours also & got in late & got two hours sleep, you may want to rethink your 25+ mile 6 peak day too)
Footwear can be problematic too, the experienced can wear lighter shoes, kids and beginners usually start in sneakers before realizing they want to hike more & invest better gear. Back in the 90's I saw a family in Teva's & thought they were in trouble high on Camel's Hump. The heavy Germanic (they were from Austria) accent showed they thought Camel's Hump was a trivial hill & in their world, it was. While coming down Big Slide, the kids and I passed a girl (maybe 18-25 but I'm not good guessing anymore) walking up the trail at a good pace, barefoot with Dad who was wearing boots.
If I get caught in the weather but had an internet forecast & weather radio and ignored the clouds all could easily see approaching from the Gulfside trail, should I have a better score than someone who's plan was to run away at the first visible signs of weather but took a longer bailout option & missed the fact that it went through a wilderness area & a bridge had been removed since their one older edition of the WMG was printed? (Hint,, a couple of SAR since the 1990's have occurred in the Dry River drainage and the DRT in the winter by people bailing off the Southern Presidentials, they planned on being on a hard packed wind slab & well packed C-Path, leaving snowshoes in the car. Crampons aren't much good in the Dry River area where few travel in winter) Bailout routes sometimes require different gear than your intended route.
I'd probably go with an Essay test over a 20 question type of format for the quiz. Ask them to write about their plans, what they did the night before, their gear and experience & give them the leeway to show their expertise or show their inexpertise. (that wasn't the first, second or 3rd choice for the opposite of expertise)