In answer to your questions:
a) The theme is not set up to separate locations by default, so this would only happen if you either set up categories as locations, or create separate instances for each location like what you see on
this site from our
customer showcase.
b) Yes, PayPal is included with the theme by default, and you also have the ability to purchase
other payment gateway plugins from the AppThemes marketplace.
c) By default, users must be registered to post reviews and comment.
d) I don't believe it does, however you're welcome to check with the plugin developer directly by posting a comment on the marketplace page. Thanks.