1. Based on certain private revelation, about 2/3rds make it to Heaven, most of which go through Purgatory first. God does not automatically throw someone into Hell just because they aren't Christian. He is not a ruthless tyrant. The ones who go to Hell are those who reject his mercy completely and would rather embrace the darkness.

2. Energy would be a more accurate description than matter.

3. Spirit is eternal so physical laws do not apply.

4. Unknown. I don't really trust those quoting exact temperature measurements, I've heard different numbers...