Will wait on the gameplay and combat loops before prediction the player counts and whatnot but in regards to how Sony will sell Fairgames, after Concord, I would be shocked if it's not a free to play game OR included in PlayStation Plus Extra/Premium but not available for sale. If it was up to me, I would go with day one in PlayStation Plus Extra/Premium. It's a co-op/multi-player game so PlayStation Plus would be required where as with free to play, it's not required. I would not sell the game at all because you have GTA with Heists and you have all three Payday games still up and running if I remember correctly.
The competition is far less for Fairgames than it is for Concord but you want to give it the best chance at success as possible. If the game has micro-transactions for cosmetics and stuff like that, then the PlayStation Plus Extra/Premium route would be the best decision in my opinion. This would increase subscriptions, possibly get people who are in Standard to upgrade to Deluxe/Premium and for those who are already in those tiers, possibly be interested enough to give the game a chance. The micro-transaction will make the game revenue on the back end.
We'll see what Sony does but if they go the $40 route, Fairgames better fucking do something unique, original and innovative as well as having one hell of a gameplay loop/hook.