Android, IOS, Back End clone -- 2

I have an app that is designed and fully functional. I however have a new client that needs the same app. I therefore need to customize/brand the Android, iOS and Back End to match the new clients request. There is an Android Code, an iOS App code and the Back End code as well. I will supply these with new skins for the clone designs. This project needs a smart, brilliant Developer who has done such jobs in the past before and who can deliver the new systems within 4 days. If Developer introduces improvements and more brilliant ways that the system could run, I will give a Freelancer Tip. Thank you.