Does the digital version of Starcraft 2 include two guest passes?
No. I didn't receive any guest passes with my digital version of StartCraft 2. I checked a day after my purchase.
When you open up the game, you have an option to "play as guest". I think that if you downloaded this game onto other people's computer, they could "play as guest" for the same amount of time that would be allocated by a regular guest pass.