Theory
Randall is Martin.
Ethan is yellow suit man.
Julie put the talismans in the cave.
Julie made sure the talisman was on the floor of the entry way in the first episode after the daughter opened the window. Leading to them having one in the RV when they crash/arrive.
Julie is Kay Dillon - Kay = Key // Dillon = Dilute/dissolve
Victor is the memory keeper of the story loop
Tabitha will be the sacrifice to break cycle
Sara won't make it past season 4 finale. Either at her own hands or something else.
It was Ethan on the radio not Thomas in season 2.
I think Victor knew Julie already when they arrived in the pilot due to his comfortability towards her.