1. You can't prove a negative, so anyone who claims they know for a fact that there is no god is committing a fallacy, I'd say. It's a lack of evidence. A severe and utter lack.

2. N/A

3. I can tolerate theism in anyone. I just think it's a silly belief. Something I can't tolerate, however, is a believer who is intolerant of other beliefs while claiming to be peaceful. I can't tolerate a religion that slows the progress of science. I can't tolerate a religion that has managed to elude separation of church and state. That sort of thing.

4. No.

5. I believe in feelings of spirituality. Being an atheist doesn't mean that I'm an emotionless drone with a computer brain or some other such nonsense. I can lie on the beach at sunset and be momentarily overwhelmed by the scenery. I can go on a walk and experience a feeling of peace. The difference is that I don't attribute these things to an object called "soul" or "spirit". They are just feelings. Good feelings, but just feelings.

6. It is certainly possible.

7. I'm not well-versed enough in cosmology to say with certainty what I accept as true, but given how well science fares compared with religious explanations when it comes to other things, I'm going to bet that the current scientific answer is much better than whatever religion has to offer.

Your questions have been answered by the Atheist Road Warrior! Awwww yeah! I'm baaaaaaaaack! Bwahahaha!

(Just kidding. No one kill me.)

*edit*

Removed a potential ad hom.