They're running Pokémon Go Card game tournaments Saturday and Sunday, Niantic hasn't mentioned anything about Gen Con ever so I'm ignoring that piece. The only related byline would be if an event is running in game after Zapdos Raids are done but that's be for running around Indy for stuff. Via their website it's a free event from when they open to when they close: Players participate in a series of daily and weekend POKEMON GO related challenges and contests for prizes. What the prizes are no idea. I guess it's like the Trainer Rewards program possible to promote their company.
Last year there was an event where people were going to do a lure party or sorts I think and they sold most of the tickets to cover cost. People started saying the didn't want to pay and would just show up and use the lures since they wouldn't be able to tell who was just on their phone and who was actually playing walking behind the crowd so tickets started getting returning (probably people realizing they could just mooch for free versus a few bucks) and the event was canceled.
If you found their booth and check it out and it looks fun good luck. Don't know how much free time I'll have once Thursday starts. I might check it out as well but it sounds like a possible pokemon Scavenger Hunt. Don't want to miss events over this I paid for but I might try and check things out while I'm there.