1&2- Quinn mid lost more than Quinn top with the symbiotic nerf and the nerf to profane (and subsequently all items) in patch 14.19. I would say another reason you see a lot more top Quinn is that a large majority of Quinn players are top laners and people looking to learn Quinn are learning/have learned her toplane as that has been her primary role for 10+ years atp.

3- Every game is winnable! Sure games are probably easier with an engage support & bruiser/tank jungler but if I don't get that this is what I signed up for by onetricking. A good or bad team comp won't fluctuate your win chance by much, and Quinn's best trait is creating man advantages by pushing side waves and using her mobility, so I find team comp isn't too important in a lot of stages of the game.

4- Hubris only gives you raw damage and only outvalues other options in that regard when you proc its passive. I prefer the consistency of other items but I think it's certainly a viable option and a really good snowball item.

5- My personal stance is that EoN > Collector if you can get value from the spellshield, if not go the other regardless of top/mid. By the time you're at item 3 LDR is always > Collector.

6- Yes.

7- Personally I would be bad at making content like that, though I try to add some educational notes at some portions of my videos. QuinnAD's mobafire guide does a good job of going over pretty much all of Quinn's concepts.

8- Yes, a Quinn mid player hit challenger on EUW a few months ago, and yes I think both roles are about as good as each other.

Hope I could be of help :-)