As wrote in the title, it seems you don’t understand the meaning of the 'exclusive '.
Please correct the word from your game.
In each arena, you used this word for an usual or abundant (not special) Dino in each arena. However, the dino expressed as ‘exclusive’ in each arena is also inclusive any other incubators in other arenas.
Even in Arena 7 or 8, the incubators include the dinos expressed as 'exclusive in Arena 1, 2, 4, 5, and 6. The dino in Arena 3 is also always inclusive in gold line incubator.
Therefore, they are not ‘exclusive’ but all 'inclusive ’ or most common dinos.
Please correct this word from your game in order to avoid any misunderstanding like me.