I went and recruited Agni first to see that scene between her and Shaedra, and the Harpies won't fight me anymore, but now I can't get Zhara. Is there any way to still get her?
I made a save recreating your path, and the harpies aren't even spawning after Agni meets the Harpy Matron. I helped Shar and upgraded the Wayfort once thinking that might work, but I got nothing. Probably a bug.