Going forward, any plot vacated will be in the following lottery when it starts (presumably 4 days after reset tomorrow when this lottery ends).

Think about it this way. Saturday at 11am EST, all these plots will have a winner. That winner has until Wednesday at 11am to claim the plot. When they do claim it, if they were relocating, that old plot will be vacated but not be available to put in a lottery ticket yet. When 11am Wednesday rolls around, it will be added to the lotto with 5 days to bid. Also, keep in mind that the way the text on the lottery system reads, if a private house is vacated in wards 1-18, it becomes FC only. And if an FC vacates a plot in 19-24, it becomes private buyer only.

And that's how it will be unless SE changes the rules.