1. The entire point is that there are many, many different lists of "7 wonders" and NONE of them are official. None of them are correct. Choosing one to be correct "to you" is absolutely, 100% arbitrary. The only one that can remotely be thought of as correct is the first one (that we know of), the list of wonders of the greek world. So yes, Stonehenge *IS* a "7 wonder of the world", according to some authors. You don't get to pretend to be an intellectual if you don't see how all of this is completely arbitrary. The list of 7 wonders that you used, the one that includes The Great Wall of China and Taj Mahal, is a very modern invention (it's only just over 20 years old) and is no way, shape or form an "official" list. By no merit is that list more correct than any other. If you're even remotely as serious about puzzles as you claim to be, you need to make it clear that you're referring to the "New7Wonders" list of wonders.
2. When you're doing a quiz, you either know the answers or you don't. Sure, most of the math questions you can logic your way into an answer but for the other two quizzes, if the player doesn't know an answer, the only way for them to get a different result IS EXPLICITLY TO BRUTE FORCE. It doesn't matter how much you don't like it. Because you have chosen to make it a quiz where there WILL be player who DON'T know all the answers, there is no way within the game to gain the knowledge to solve those questions EXCEPT TO BRUTE FORCE. Because of how YOU designed it. So you don't get to design it in such a way that brute forcing is the only option left to these players and then say "I don't want my players to brute force". What other options have you left them???? Literally nothing. So all you're doing is forcing them brute force those answers anyway, except the way that YOU'RE doing it CURRENTLY, the process is absolutely horrendous to play through. Just because you're being obstinate and clearly not even understanding how the game plays out for many of your players, the gameplay experience will be a lot more horrible than it needs to be for any reason. People just want to play your game. Why do you take satisfaction in making your players get stuck with no ingame way to move forward? Stop thinking about the game from your perspective because you ALREADY KNOW THE ANSWERS. Anyone can design a quiz that they will solve 100% of the time but that many other people will fail. There is no accomplishment in that. Just focus on making it an actually good gameplay experience instead, which involves letting players know how to proceed without looking up a guide or googling answers.
3. Typing in their names absolutely does not constitute a "challenge", it's just more useless obfuscation where the player already knows that answer for 100% sure but they can't know if they got that answer right because they have no idea how you chose to grade it. Again, because you don't tell your players when they're correct, they have no way of confirming how they should enter the names. All they see is they got X amount of answers wrong so when doing the quiz again, how are they supposed to know if the way they entered the name last time was counted as correct by the game or not? Even though they know the answer for absolute sure. Do you see now how your approach is so horrible for players? It's a nightmare for players who have to do the quiz again. They're likely to get an even lower score on the next try because they have to second guess almost all of their answers, EVEN THE ONES THEY GOT RIGHT. It would take literally forever to pass the quiz in this way, especially considering how many clicks it is to get through another week of answers just to see how much they failed by this time.
Like you don't even tell players they need 10/15 answers correct. There is so much basic information that is just left out for absolutely no good reason.
4. Yeah, I know now that it's a trick question. The thing about trick questions is they are only really effective if you've already set up an expectation with previous similar puzzles that are NOT trick questions and they absolutely require you to know there are no other logical answers to the same question or they come off as just completely arbitrary (which they also are, in such a case). For me intuitively, the answer is 6 because 3,3,5 establishes a pattern and 4,4,X implies to follow that pattern just one higher, which is how the answer is 6. There is technically also a really complicated formula that proves that the answer should be 18 if viewed as a number sequence, but I wouldn't blame you if that's a bit too technical.
My problem is not with puzzles. My problem is with "puzzle-makers" that think their poorly researched questions constitute proper puzzles.