Q: Will the “Forced: During a duel, …” protect the character with a Breastplate attached if they refuse a duel?
Answer: No, “During a duel” timing is not the same as during a refusal of a duel. The first Forced on BP, would be after the challenge has been accepted. So the forced on Breastplate to reduce the number of wounds by one, would not trigger. The second forced, however, will trigger upon refusing the duel and taking the wounds.