Django based Web-Service needs to be extended

We have a running web service that needs to be extended. Our service is a special kind of a conversation / commentary tool that gets embedded into our customer's websites (like blogs, news sites). Our Django backend manages the data, and a customer / user database (with currently 5 userTypes like customerAdmin, contentEditor, user etc. with different access privileges) , facebook and google login. During this summer we need to add some features and make the code more flexible. (Currently some colors and display messages are still hardcoded, but we need all this editable for our customers). We have to ship a new version mid July 2016. Our current developers (who unfortunately don't have the time to do the job this summer) told us, that what we need will roughly take between 10 and 20 days of work (8 hours each) for an experienced Django developer. The backend code (Python / Django) currently has a unit test coverage of about 90%. The frontend is done with React. (We're also looking for an experienced React developer!)