WMG for the franchise in general:
Cameron Mitchell will appear, or at least be referenced.The series is supposed to feature a young Catherine Langford. "Young" is vague, but since she was 21 in the flashbacks in "The Torment of Tantalus," she would have been around five or six in 1929, when Mitchell was supposed to have arrived, and a teenager at when he stopped Baal from sinking the Achilles. Even if Ben Browder doesn't appear, there will be an oblique reference to him; i.e., a strange man who insists on staying near the gate at all times, etc. This troper always found it odd how easily they managed to manually dial Heliopolis in 1945, but had so much trouble dialing Abydos fifty years later. Maybe Mitchell was involved, secretly helping Langford?