In answer to your questions:
1) Our themes are compatible with
WordPress multisite, however there is no specific plugin for our themes to be used/managed in one admin dashboard. Each still has its own controls/functionality.
2) There is only one "type" of user as such, so they can all manage the listing the same way (whoever has listed it or claimed ownership). This is done through their customer dashboard.
3) There is no specific plugin currently available for printing coupons
4) There are no options for this built into the theme specifically for city or category, ad widgets/banners are overall. Thanks.