Facebook Pages and Apps

I am considering starting a business on Facebook that will offer a space to people who wish to buy, sell or give away "things". It must be able to work autonomously and be self moderated by it's members, likers, friends or followers (this is part of the question...which is best?) People must be able to post directly to the timeline. People must be able to receive notifications or posts direct to their own timelines without having to select that option as such (of course they can choose to opt out of this if they choose). As the business has the potential to become worldwide, can notifications be sent only to, say people within a certain radius of they're location? Can that radius be selectable by the individual? Is Facebook clever enough to use their mobile location to change the alerts/posts they receive depending on where on Earth they happen to be? Monetization. Can the public offerings be sold/booked directly through an existing Facebook app? If so, can this app pay commissions on sales to the page/group/community owner? Can members be given an option to choose whether they are buyer or seller or both? For example, someone who only sells may not want to have offerings made to them by other sellers. Similarly, buyers may not be eligible for wholesale offerings from companies that sellers may want to receive offerings from. Can this all be done on the one page or will this best be achieved using separate pages? The reason I don't simply dive in and do it, is that the name I've chosen is quite unique and I wouldn't like to create the page using the incorrect option and then have Facebook deny me using that name again to do it right. Do you know what I mean? IMPORTANT! Please confirm that the required functionality is available before you quote.