Dunno really till it starts. But the rules listed below says trainers world wide so gofesters will count I gather are the ones who unlock the mystery at gofest. If the mystery at grant park gofest is completed then we get extra special bonuses world wide which hopefully means level 5 raids for all.
"If Trainers around the world catch enough Pokémon, a mystery challenge will be unveiled in Grant Park that, once completed, will unlock an extra-special bonus across the globe. "
As it stands the event times are for go festers to catch certain types to start off certain bonuses and we out here catch those bonus types to extend the bonuses.
During the day, there will be three Challenge Windows in which Trainers everywhere will work alongside those in Chicago to unlock global rewards. During the Challenge Windows, Trainers in Grant Park will attempt to unlock perks for Pokémon GO players around the world by catching certain types of Pokémon. Each Pokémon- type will be tied to a different perk, so Trainers at the park will need to carefully choose which Pokémon they catch.
Trainers outside of Chicago will attempt to catch as many Pokémon as possible during the Challenge Windows to extend the duration of the bonuses unlocked by those attending the even
Challenge windows are 11am-11:30 am 1pm-1:30pm 3:pm-3:30pm
Mystery challenge for all to do is 6pm to 7pm
Global Reward is july 23-24th