Customize existing android app.

PLS READ THROUGH. I have an existing android app but need a few customization so you're not building something new. We need two features added to this app. 1. Wordpress plugin shortcodes to work. 2. In app chat. One way. When admin writes new message, mark users who have read. Restrict who views the message by mobile number. (So that when you attempt to open, you type your passcode (mobile number). If allowed, you view, otherwise rejects. Just to explain things, this app has a wordpress plugin which allows you to set categories of posts and menu to show in the app. Sort of controls what's shown in the app.