thanks for trying out Azure Mobile Services. Here is a good tutorial on how to get started with Android.
To answer your questions specifically:
- Generally a CRUD API for data storage and a custom API for arbitrary REST calls should be all you need for a straightforward app, and those are all offered in the box with Mobile Services. The one thing we don't offer today (but are considering) is support for duplex messaging (WebSocket), which you might need if you are building a realtime app or game.
- Mobile Services does not support object trees on the client, but you can still have them in your server database. You just have to write some custom code to "flatten" the hierarchy before you send it to the client.
- Every mobile service supports HTTPS by default. We do not currently allow you to do a custom SSL cert.