Here is the way people answered to me about some of these questions:

1. Apparently they built the ark over along period of time and I'm pretty sure that Noah had money to hire people? The bible said that people laughed at him so a lot of people had to know what was going on.
2. The geography of the earth was not the same before and after the flood. To quote Genesis: "all the fountains of the great deep burst open" which might mean earthquakes that shifted the topography?
3. A theory is that they were hibernating for that period. The whole thing was a miracle so why not that?
4. In the Bible animals are semi seen as below humans so meh..
5. 71% of the earths surface is water, no one knows what it was like before unfortunately.
6. It is generally believed that there was no rain before the flood.
7. Small dinosaurs or eggs might have been brought along.
   8&9. Back to the hibernation theory.
8. All the animals came to Noah, he did not collect them. It is believed that only the main species was aboard the ark and micro evolution sourced the sub species.
9. It was a miracle, God sent all the animals.
10. Genesis 6:20 - Two of every kind of bird, of every kind of animal and of every kind of creature that moves along the ground will come to you to be kept alive.
11. No clue..
12. Diseases develop or sometimes even lie dormant for years in people.
13. Those little buggers float and maybe some survived on the ark.
14. Micro evolution, not sure what else to say.

That is just my two cents on the matter.