Wordpress Website with Booking Engine + Integration API Custom Service for Channel Manager Airbnb Booking ecc.

We need to create a fully working integration between a wordpress website with a theme that include a booking engine for apartments (with geolocation filters, checkin date, checkout date, adults and children and others filters) and a channel manager that have to share with the wordpress website the calendar availability and all the apartments informations by the Channel Manager API. In particular we need the following functions: 1. To Import and Synchronize calendar availability, price and all the information for all the apartments that are loaded on the Channel Manager (so we don't need to insert new apartment or to upgrade them with updated information. Even if one of the apartment has been booked on Airbnb, the channel manager will be updated with this information and by the API we need to update consequently the wordpress apartments database). This function can be managed by a cron that automatically do the synchronization. 2. The WP theme booking engine (the booking button and also the search button) must be connected to the Channel Manager API, so that when we receive a booking from our website, we can update the channel manager with this information and it can update the other marketplace with the new calendar availability, to prevent any kind of overbooking and to manage the fresh booking received from our website. Theese functions can be quotated separately, we need to know a price and a developtment time for: Entire website development in Wordpress with Booking Engine theme (that we will buy on Themeforest) and functions 1 + 2, and a quotation for this 3 steps (entire website development + function 1 + function 2). Please define correctly price and timing for each point and be carefull that we will pay only for a full working solution delivered. Delay over the 10% will cause a changing of the final price.