what belongs in your concrete facade's init() method other than a sendNotification() to trigger your AppStartUp Command?
Usually we call that convenience method startup().
In a very complex app, dependencies in the startup order can get hairy no matter what your choice of framework (or lack thereof).
But in PureMVC, the recommended startup process goes like this:1) Prepare the Controller.
This can happen in a command or in the initializeController method of the facade, and consists of registering all your commands.2) Prepare the Model.
This consists of registering Proxys and they should not go ripping off and making service calls as soon as they're created or registered. They should wait for invocations from Commands or Mediators for doing anything, because if they got a service return before Mediators involved in the response are registered, you'll miss it.3) Prepare the View.
This usually consists of registering Mediators, and upon registration, Mediators frequently request data from the already-registered Proxys.
I recommend picking up a copy of the ActionScript Developer's Guide to PureMVC, as I covered this in a pretty high level of detail there, and particularly into how to reduce the size of your ApplicationFacade to nearly nothing.
You can peruse the example project from the book for free by downloading it from http://oreil.ly/puremvc