I did the maximum of 600 reputation (6 x the splendid gravestone) and got this loot (screenshot attached). Well, considering how easy it is to get all the stuff for the gravestones (you don't even have to enter a red zone) I'd say it's OK for new or medium players, but not worth the effort for high level players like me. I still have to find out what these Treats do (1st row, 4th from the left). BUT at least the pumpkin field popped up again and the boss was Freddy. Can't say if it was coincidence or the game knows what boss you are missing.