16 Jun 2023
If you only have one card in your library as Gollum, Scheming Guide's ability resolves, you'll look at that card, put it back on top of your library, and then continue with the ability as normal.
16 Jun 2023
If you have no cards in your library as Gollum, Scheming Guide's ability resolves, your opponent's guess will not be right no matter what they guess. That means you'll draw a card, or more accurately, attempt to draw a card from your empty library and therefore (usually) lose the game.
16 Jun 2023
You reveal the card even if your opponent guessed correctly.