I'm fairly convinced that it is not a reference to any other past Lego product, but was designed entirely for this set. It's hard to prove a negative, so while I list three reasons for this, none of them is a complete proof and all these could be false.
As far as I know the only Lego games to feature ghosts were either based on the Ghostbusters franchise, which uses different aesthetics, or had different ghosts (like that of Vitruvius, various characters from Star Wars, Harry Potter, Lord of the Rings, or the characters Ghost Rider or Beetlejuice), which do not look like the ones featured on these stickers.
Which leads to the second point: there is the computer screen in your picture, but a laptop is included as well with a similarly themed screen: It would be strange to include a reference to the same thing twice in the same set, but if course it still does not prove anything.
The third point is much more intangible, being based more in the reason of meta-knowledge. When Lego designs a set like this, it is primarily meant to be played with. In this set, the focus is on catching ghosts, any Easter eggs are of secondary importance at best. But if the green ghost screen were a reference, that would make the other similar one a reference as well, resulting in a set with no screens dedicated to the primary play function. Which, of course, while highly unusual, would still not prove anything.
So these are the reasons for my conviction that these are not references to anything from the past but were created specifically for this set (or product line).
Or one might argue that the sticker is referencing the Lego Hidden Side application, but that would be stretching the definition of a reference, as the application is specifically designed to work with this set :)