Skilled mobile app developer for adding features to an (existing) app

We're looking for skilled, creative and talented mobile app developer (team) to help make two custom additional features to an (existing) app made with an app builder. The two features that needs to be added to the app is a voicecall feature like Apple's FaceTime and an appointment sheduler&reminder. The features and app must be compatible for both the AppStore (iPhone and iPad) and Google play (Android). Applicants must be very experienced developing mobile apps for both the iPhone and Android devices and able to show examples of their work. An excellent grasp of English is a must. The requirements are as followed: - Someone who can not only program but can also have excellent UI/Design - Someone who has at least 300 hours on Freelancer - Someone who has a 5 star rating - Someone who takes pride in their work and makes polished looking products - Someone who speaks English very well - Expertise in cross platform supportive frameworks i.e. Seatlleclouds - Have good Analytical skills to present accurate estimates Please reply with: a. List of top 5 apps you've created. b. Your best performing app in the marketplace (AppStore, Google play) c. Your best portfolio app/item. d. Examples of work including any UI design examples you have done before. ***IMPORTANT: Please put the words "read me" in ALLCAPS in the first line of your reply! If I like your previous work, I will reply and give you more details. I know that this will be a fun project for the right person. Do not bid unless you will enjoy this work and you're willing to work on other projects in the future with us. So serious inquiries only! I look forward to your proposals, Hung