For iOS the flow goes: UILaunchImage -> Corona Splash Screen -> Your first screen.
For Android it goes: Corona Splash Screen -> Your first screen.
Apple still requires either static launch images (Default-568h@2x.png to get out of iPhone 4 mode, Default-667h@2x and Default-734h@3x.png) to get out of iPhone 5 compatibility mode with the new phones. Or you can use a Storyboard based launch screen.
You have to have one of those to pass Apples automated tests. See: https://docs.coronalabs.com/guide/distribution/launchFile/index.html
If you’re using 3037 or later, we recommend using the Storyboard system. That’s the daily build where we dropped iOS 6 and 7 support. If you’re using older versions and you want to support the older OS’s, you should continue to use the Static method since Storyboards were introduced in iOS 8
Rob