Does Disney World have a consistent calendar of extra hours?

Does Disney world has consistent days of the week that they have “extras” at the different parks? For example are Early Morning Magic/After hours always on a certain day of the week for a specific park? What about the free Extra Magic Hours? Will we know the park hours and “extras” BEFORE the 180 day dining reservations? Do they ever do extra magic hours at two parks on the same day? Do they ever do morning and evening extra magic hours on the same day at the same park?

They say in advance what days EMH are but they can change at any time. Usually only one park has them at a time is what I have seen but I may be wrong at different times of the year. I also have never seen both day and night EMH. Suppose it could happen but I have never seen them and I have been to WDW about 10 different times. :nerd_face: