1. No. Believing is not something that we "choose" to do, but rather it is a product of the knowledge we possess and our brain's processing of said knowledge. You could tell someone that if they were to start believing in Santa Claus that you would give them a million dollars, but even with that incentive a person couldn't choose to just believe because that belief would be in conflict with reality and the facts that they know. As an atheist, I couldn't willfully decide to believe in God, because said belief in my view is unfounded on evidence and contradicts with the way I see reality. Belief is not chosen but realized.
2. I don't believe in an afterlife and obviously this question is somewhat in conflict with my views about belief as briefly outlined above, but I'll answer anyway. If heaven and hell were to exist and the only criterion for admittance to either was whether or not you chose to love God, then yes it would be a choice in the strict sense of the word. This choice, however, would be the same type of choice that (prepare for stale example) a Mafia boss would present to a store owner: pay us money for "protection" or something bad may just happen to you. Obviously, no one wants to be murdered, so paying the money is the only sensible "choice", but this choice isn't really free and the obvious choice of doing neither is excluded. I've heard people say that atheists choose to send themselves to hell by choosing not to love God, but this is the same thing as a robber saying, "Give me your wallet or I'll shoot you. Don't make me shoot you." God set up the conditions for being admitted and humans have no say in them and are effectively having the gun held against their heads. Technically it is a choice, yes, but I don't see how anyone could honestly say that it is a fair choice.
In addition to this, the omniscient quality of God that most believers espouse would cause problems. Someone could easily claim to love God and believe in him, but surely an omniscient god would know if the motive for his belief was merely to save himself and wasn't genuine. This is a reason that Pascal's Wager fails as well. Yes I could profess belief in God as insurance against hell, but I wouldn't truly believe because you can't make yourself believe and an omniscient God would know that.
3. Don't believe in afterlife, so irrelevant to me really. Speculation on what heaven is like is really pointless and I am amazed by how Christians will speculate about and claim that we know what heaven is like. Our teacher once held a discussion in class and was asking a fellow student about what he thought, so I asked whether or not you could have sex and heaven. He was stumped at first then said, "Well, once your wife dies you can have sex with her but before then no." I was mainly amused at how he said this obviously having no idea whether or not you could. This reveals another tendency of believers that I have noticed which is being uncomfortable with not knowing. People rampantly speculate on what heaven is like with absolutely no evidence and everyone will vouch for their own ideas, but wouldn't it be best to simply say that we don't know?
I could discuss the implications of this question if God were to exist in much greater depth, but this post is long enough as it is.
4. I don't believe in a God, so in my view your question is flawed, but again I'll answer anyway. I wouldn't believe in a God who interferes in the universe because there simply isn't any evidence that he/she/it does. Everything attributed to the hand of god is explainable by some other means. The only type of god I see as even remotely plausible is a deistic god who basically started the universe then moved on. If there is a God who intervenes in the world, he/she/it goes to great lengths to make sure that said intervention is virtually undetectable. In my opinion, when you free yourself from prejudice and impartially look at the world it is clearly untouched by supernatural hands, and I see no reason to try and distort my perception of reality to make it seem that it is. This is a good video somewhat related to this, and this guy makes great thought provoking videos
http://www.youtube.com/watch?v=jrX__ILDd3w.