I would like to support my iPhone\'s app Local Notifications in the Apple Watch from the very first moment the Watch is released, but I don\'t plan on building a Watch App yet.
I would like to support my iPhone's app Local Notifications in the Apple Watch from the very first moment the Watch is released
Yes notifications for your iOS application will work from day one on Apple Watch.
Will notifications on the Watch have action buttons just like configured for the iPhone app?
If your iOS app already supports actionable notifications they will work with Apple Watch.
Is there any way I can test that on the simulator to be sure it works as expected?
Good question actually, you can't test your current iOS app's notifications working on the simulator but you can test a custom notification interface from WatchKit.
You should file a feature request for this.
Is there any way to support only notifications without creating a Watch app?
No, you'll need to provide a sample Notification JSON payload as part of an WatchKit Bundle, which requires submitting an Apple Watch app.