Just a couple questions

[Pyriis]

Being new to the game, as I have only purchased the first set.. My friends and I have a few questions, that either I over looked while reading the rules, or they are not clarified.

1: If a friend of mine is fighting a monster, and I have 2 cards that add +10 to that monster, can I play them both?
2: How many cards can I play during another persons combat? If someone is fighting a Zombie, and I have an undead in my hand, can I play it, a Mate, and 2 +10 all at the same time?
3: If I am wearing the flaming Armour, and I kill the chicken that says if defeated with fire gain an extra level.. Does that count as beating it with fire? If yes.. Can that allow me to win the game if I am level 8?

I am sure I have more, I just do not remember them.