My situation is pretty similar, but a little different. I am able to get to the point where I can talk to Durance about how I think Magran was allied with Woedica, but I only have 1 option other than "It's just a feeling I have". I've used all the dialogue options that aren't restricted like elfbarf, but I can't progress any further. The only quest I have left is this and the main quest.
Here's my save if it helps.