@Rob: Hey there, I am a bit confused on the question I guess.
For traditional iOS/Android we use Storyboards/Android XML separate user interfaces with shared code. Our designer for iOS will automagically set the Outlet when you update the name of a control in it. This way you don't need to update any headers or anything like that, it just generates the code.
There are a lot of different routes that developers can go for MVVM and DI code. Xamarin.Forms itself has a full dependency service built right in. The team was really familiar with Autofac so they used a bit of that in the app.
The great part about Xamarin apps is that they are .NET apps so you can use what libraries you and your team feel comfortable with :)
@mrjimmy: Yes a mac is still required to compile your entire application to install on device or simulator. With the live player we are interpreting your source code, not compiling or installing your app.