I usually kill Ethel right inside her tree entrance, before I even get to the masked people. But, the people wearing the masks are still kinda dumb. One of them will actually talk to you but the other 3 are in denial basically.
Now that you mention that, I think that is how I triggered the dialoge between me and a masked servant. On my next playthrough as a Cleric, i'll try to remember to do that. As well as trying to remove curse on them.
