Theremin could try. However, he's from the third faction (Helveki), so likely they won't think much of him. You are in a village of descendants and veterans of Essen, and the attackers were from the Imperial side of the three-way war. You do have some factors on your side. Theremin has high Charisma as a bard; Owyn is Imperial; and you have prisoners you could return or use for negotiation leverage. There may be other factors, depending on what you say.