I wish we could have seen the conversation between Cassandra, Julia, and Professor Stokes. Professor Stokes knows that Barnabas and Julia believe Cassandra to be a witch, and Julia knows Stokes knows it. They had, by Julia's account, a fascinating conversation about the occult. Did Stokes at any time try to lead the conversation to find out more about Cassandra? It would be risky for him to do it, but Stokes has enormous confidence in his own ability, so he might try it.
Roger and Cassandra come across as a harmoniously married couple at the moment, and I'm wondering just what Cassandra is doing to keep Roger happy.