e.g.
Battle: Target your unbowed attacking Personality. Move a target enemy Personality at any location to the current battlefield. Straighten him as he moves.
Interrupt: Target your Yojimbo. The action must target him, if legal.
All actions a player takes in battle – Battle actions, Engage actions, or even Interrupts during a battle -- follow these additional rules: ..
Rules of Location: ... 2. To be legally targeted by an action during battle, any cards in a unit must be at the current battlefield.
I think this means that Final Sacrifice can only target a unit at the current battle. So if Isawa X and Shiba Y are at home, and Shiba Z is defending, and the attacker plays Determined Challenge on Isawa X, Final Sacrifice can only target Shiba Z (a legal, if useless target for Determined Challenge) but could not target Shiba Y to cause him to be moved into the battle. Correct?
And therefore,
Battle: Target your unbowed Samurai and target a Personality in the Defender's home. Straighten his unit. The Defender may move him to the current battlefield. If he chose not to, he loses 2 Honor, dishonor the Personality, and you may draw two cards.
While nothing stops you playing Final Sacrifice in response to Coward, it will never do anything, since Coward can only target units at home and Final Sacrifice can only target units at the current battlefield. Correct?