Florida schools will long be out by early June; that won't be an issue.
What CAN be an issue is weather. If there is rain with any lightning in a 30 miles radius, they will close the waterpark and shut down all of the rides; you can get stuck there with nothing to do for hours.
Weekdays are better because locals who work mostly won't be there, but if the day is rainy, stick to Disney or Universal if you want a theme park day, because
Legoland will just freeze in place until the rides dry out, and almost nothing there is under roof except the restaurants and the gift shops.