Example from my own writing:
He wouldn't have guessed (that) there would be someone with diarrhea in the toilet. Or that the ferry's rail would be half his size. Or that the night would become dark, windy and rainy, making it impossible for the ferry's crew to find him in the water."
I think the first that is unnecessary. But adding it would make it symmetrical to the other sentences. Is this something that writers usually do? Or I should just omit that first that?