1. See "Fist" in the "Weapons & Armour" section of the rulebook (p.24)
2. Nothing, they have no weapons to lose.
3. Broken off, bent out of shape, however you want to explain it - there's nothing in the Fighting Claw rules to say they ignore it.
4. Ghouls don't use weapons as such, so it doesn't affect them.
5. Unarmed combat.