Customization of a WordPress Theme

I need an experienced developer who can customize and add some features in my existing licensed, paid theme called ListingPro ([login to view URL]). I am using the theme in my directory website. I have created a site like Yellowpage with different businesses listed. It already has the system of taking bookings from a listing. Example: Doctors/Lawyers can use the system of taking appointments. Please see this video to understand: [login to view URL] We can implement PayPal or Stripe. I need the system of collecting payments so that the person who is taking the appointments can also collect his fees set by him from my site. I should be able to get a commission like percentage-basis or fixed rate. There should be system of rescheduling, cancellation and Events creation with ticket selling feature. We can install it in Child Theme. You can either develop Plugin or customize the theme code. I think plugin would be better. If you customise theme, what will happen after next version update of theme? Lowest bidder will win the project. Installation and running the plugin and site smoothly should be your responsibility before getting the milestone released. Example: [login to view URL] Please ask me questions in chat.