Now you can ask your users to rate / review your app while they are using it (so they don't need to go to the App Store) and respond to reviews too! See the attachment
this is not a problem getting a developer - but the problem is that BB is a closed platform. you can use it in xcode like a native code. and soon all apps are going to be required to implement that.
I don't understand. Buildbox can export an iOS project so you get access to the source code. Also, as far as I know, you only have to do it if you want to ask for ratings. I haven't heard it's required. But someone correct me if I'm wrong.