Hotel, Conference Venue and Restaurant Management Subscription App and Desktop Site

Application Type: 
Hybrid (IOS, Android and Desktop)
Brief:
I  want to build a hotel management with venue (conference rooms) management and point of sale and e-menu for restaurant, the 3 parts should be as add on's or independent based on the permissions they have. Should be a website and an app, with subscription and one time billing for the software . 
Hotel: different room types with different rate codes, calendar view of rooms rented reservations and available, reporting, billing 
Venue: calendar of  conference rooms , calendar view of rooms rented reservations and available, reporting, contract management( have different contract templates), billing 
Restaurant: menu with photo uploads and billing, Chat feature

Some Similar Apps/Websites: 
Conference centre Management : www.skedda.com, https://www.eventective.com/ https://www.banqueteasy.com/ http://ejantri.com/
Hotel:  https://www.hotelogix.com  https://www.ezeefrontdesk.com/  https://www.frontdeskanywhere.com/
Restaurant: https://slickpos.com/  http://www.foodenginepos.com/ https://www.touchbistro.c

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Features:
Email Signup/SignIn
Social SignUp/SignIn (Facebook, Google, LinkedIn, Twitter)
Push Notifications
Deep Linking
Calendaring
Social Engagement
Subscriptions
Shopping Cart
Payment Processing
User Analytics
Crash Reporting
Multilingual Support
SMS Messaging
Real-time Chat