1. Its once per battle for the ability. So if you decide to only use one flask, you can't use the others later.
2. It does one mortal wound to the whole unit, which is allocated by the player who owns that unit.
3. Same as 2, it's 1d3 for the whole unit.
4. Wounds are allocated to her last because (if she were chosen first) if she were slain by that ability, an argument could be made that no one else takes wounds as nothing is within 3", as she's not on the board. Mostly it's there for clarity.
