Hello, I am very interesting in your job because we have already developed several Android apps using Facebook.
Facebook Graph API supports many functional api needed to co-work with Facebook such as login, search friends, search post..but Some functions are DEPRECATED in Graph API v2.x, such as Send Message, Wall Post..
I already resolved it using WEB AUTOMATION.
If you want to send message or wall post, you cannot use Graph API v2.x.
In addition, I can developed WEB SERVICE using PHP to manage app as well as ANDROID APP.
I am new freelancer, but I believe I can developed more faster and cheaper than the others because I am expert for your job.
Sincerely.