Q. Can you feed Black Dragon every turn with Feeding Frenzy, even when it is a monster, to keep it a monster every turn?
A. Yes, you can continue to feed Black Dragon when it's a Monster. So if you have Keaton out, Black Dragon can attack every turn.
Q. Can you have more than one of the same pet on the playing field at the same time?
A. Yes. Pets are item cards and you may have multiples of the same items.
Q. What happens when your opponent destroys your pet while it has cards under it? Do they go the the discard pile or back to the bottom of your deck?
A. If a pet has cards underneath it when it's destroyed those cards go to the discard pile as well.
Q. How is the damage dispersed? In sets of 10, 20, or 30 (depending on how many cards you put under your deck) or in groups?
A. Porcupine does it's damage is packets of 10, just like any other card that does damage based on X of something. It's going to do that damage to the monsters, then they will die off if they didn't have enough hit points. It will then do it's damage to the player, again in packets of 10. If one monster is left on the board, no damage to the player.