MonoGameTeam/Community don't really do anything for specific platforms, IE achievements, avatars, networking.
Microsoft crapped on indies in the past. Even today you're probably going to have to jump through hoops to truly access Xbox Live, Xbox SmartGlass, etc.
You can try XNA 4.0 Refresh to target Windows Phone 7 - 8.1, but how much you can use may depend on Microsoft's blessing. With any luck, what you're wanting will be accessible by XNA alone.