As off now allying with the duke is the worst option , scene and probably enjoyment wise. (Its mostly a "you want to do some good, look at how the twins now know everything , you get nothing and the whole rastedel thing is one bad thing after bad thing until you regret having saved delane to begin with) probably will get better after we leave chapter one and Rowan starts to maybe be able to do things go his way, for now we only have the beginning without any aftermath that shows it was worth more than a kick in the balls followed by a slap in the face.
My sugestion is go first with countess because she has the 2 options on how to corrupt her, then the copper.