Rules question: no attackers at resolution

By Ishi Tonu, in Legend of the Five Rings: The Card Game

I attack with a Matsu Berserker

Province revealed is Rally to the Cause, conflict type switched to Political, Berserker goes home bowed

So now there is an attack with no attacker. As I understand it, my opponent would still have the option to assign a defender to win the ring, or could decide not to send any defenders and the ring would go back to the unclaimed pool.

If my opponent chooses not to assign any defenders would they still lose 1 honor for unopposed?

If my opponent assigns a defender with 0 skill, would they still claim the ring on defense?

Thanks in advance for any help.

Thanks a bunch. If I could double like your response I would.