Questions about Undertale on the Store

Hi there.

1. I was wondering if by purchasing the game I'd get the PS4 theme or if it was just a preorder bonus.

2. In the Vita item it says that it gives you the PS4 version as well (crossbuy) but in the PS4 item's description it doesn't say anything about the Vita version; I've heard stories of games that are only one way crossbuy.

3. If the PS4 theme comes with the PS4 version, if I buy the Vita version and by extension I get the PS4 version, will I get the PS4 theme?

And for context; I'm planning to play it mostly on my Vita, but the PS4 theme is really nice so I want it if possible.