1) No. Check out the Terms of Service and Acceptable Use Policy. They forbid selling or giving away computing resources to others. All the sites under your account must be "yours". If they didn't have this restriction, you could open up your own hosting service for $6.95 a month (at least, 'til you ran out of bandwidth, storage, or some other resource).

2) That sounds questionable. You're talking about selling or giving computing resources to others to operate their own forums, rather than your running one or more forums yourself? See #1.

3) I'm not sure what you're trying to do here. Why bother buying a Lunarpages account if you're doing the hosting on your home PC? What are you trying to accomplish?

4) No. There are plans where you can buy 3 months at a time, but it's considerably more expensive (per month) than a 12 or 24 month plan. You have to pay the full term of the plan up front. Don't forget that there's a 30 day money back* guarantee.

* except for non-refundable items such as setup fees

5) If you pay by credit card, the hosting account can be up and active within a few hours. Other payment methods take longer to clear the bank. Once your domain name is obtained for you, it takes anywhere from 24 to 72 hours for the news to spread around the world via the DNS system. In the mean time you can use a temporary domain name of the form <SERVER NAME>.lunarpages.com/~YOUR_ACCOUNT.