Wow, great questions.
1) Venus is orbiting the Sun, similar to the way the round-earth theory predicts Venus's orbit.
2 and 3) I grouped these together because the answer is similar for both
The daytime and nighttime pattern is caused by refraction of light. While Earth orbits the Sun, it orbits sort of facing the Sun. However, it's not a perfect 90-degree angle, it's off by quite a bit. As it orbits the angles continual change means the light reflects and refracts in the atmosphere differently. At some points all light is reflected away, creating night. At other angles, more light is let in, creating the day. If all the light is being refracted, then the Moon and Sun become invisible, presenting a rising and setting pattern.
4) I think this question is a bit unfair. Really, no-one knows. Round-Earthers call the force Gravity, but if you ask them how gravity works, or why you'll find they don't know. Gravity is really just a name for their ignorance.
5) Again, this deals with my answer to 2 and 3. The moon is a disk circling about the Earth, as it's angle to earth's surface changes, so does the light that gets reflected. Some parts get reflected, and some parts don't (this is responsible for the crescent moon).
6) Again, the light from that part of the moon is all reflected due to a changing angle.
7) The moon passes in front of the Sun.

That's quite a loaded question, I could just as well ask you "Why do the Sun and Moon have a flat circular shape?" I think the spherical shape of the planets is exactly what we're debating.
9) Nuclear Fusion, just like Round-Earthers. We don't throw out every bit of science ever discovered you know, we're just skeptical about the earth being round.
10) A couple of reasons 1) It's cold and uninhabitable because it never sees the light from the Sun it is always dark and freezing. Living there would be impossible. 2) Governmental influence is another big factor. I mean, imagine if they really did let people go to the edge? That would shake society to its core, not something the government wants. 3) Because of the circular motion around the Sun, the edges of the Earth are curved up. This means 1) HUUUGEEEE mountains, where there is no air, and very very cold conditions. Also, because the mountains are so high, they are subject to a lot of Space radiation and the Van Allen belts.
11) Again where is a definitive model of the Round-Earth theory? This question could be asked of both camps.
I hope that clears things up!