You can have as many Facebook account as you with as long as they ALL have their own email address. I tend to make one Facebook account for the games I play. Example...SimCity BuildIt I have a Facebook account that I have linked my game to. If I choose to restart my city, I will deactivate that Facebook account, and make another one for my new city. I will NOT link any other game to that Facebook account. At one point I had 7 different Facebook accounts for all the different games I played, plus my personal Facebook account that I only use for family and real life friends.
Good luck.