Ignoring Isobel

I'm going for the save all the tieflings trophy and I don't want to risk last light inn with any fighting, I also kind of don't want the harpers on the doors to die because I'm a softie. Can I just do all the other stuff at the Inn and ignore Isobel? Do I have to talk to her to get her in camp with Aylin later (planning on freeing Nightsong)

Thanks, input welcome =)