oh wise ones! are there extra magic hours on Memorial day monday usually? planning for 2018 hoping to book the BBB at Disney Springs on the day before we go wanting to avoid early magic hours if we can. 
The truth is that no one really know exactly to far in advance which days and parks are going to have extra magic hours. I do not know if past Memorial days have had them but someone else out here may be able to supply you with that answer.
You can look that up on the historical crowd levels page, Historical Disney World Crowds. You can click on May of each year, and scroll down to the Monday of Memorial Day weekend. Click on it, and you get the hours and crowd levels for each park that day.
thank you!!!
Looks like at this time, there is AM EMH at AK. No other parks have it. That’s not to say that they can’t add it closer to the date.