>What exactly should I make the launch screen of a SpriteKit Game be?
Have you composed any meta data screenshots yet? No need to add your logo where it doesn't already exist...users have already bought in.
The launchImage won't be seen consistently...only on first launch/not when a session is restarted. I'd keep it simple, with just the basic elements the user sees the first time they use the app.
One way to gather ideas is to check out some of the more popular/professional games in the store. Check a few to develop an aggregate scope, etc.
>you can't just copy-and-paste from a Sprite Kit Scene to a Storyboard?
If you do a live screencapture, either on the device or via simulator, you can use that view as you desire. Try cmd-cntrl-shift-4 all at once, then hold and drag across the exact region you need, then open Preview and use the menu to make a new image via the clipboard. Confirm dimensions, save/add to the project and use as required for launchImage.
As to what's allowed, my opinion is that review will look to make sure what they see matches the rest of the app - it's a problem if two different stories are told. Be consistent. Not sure how much branding they would pass judgement on. Again, the user already has the app, so no need to go overboard.
