I wrote two essays describing the school I was applying to and the type of candidates they would prefer to have. I took excerpts from Ms. Leopold's interviews conducted by Boston.com and BW and used them in one essay to show what she means by leadership, and what kind of leadership she is seeking out in a candidate, and what other qualities she'd want to see. For the second essay I wrote about the history of my chosen school (applying to only one), it's culture, faculties, specialisations, and statistics - taking details from the school website. On top of that I had a lunch meeting with one of my recommenders, I work with the second recommender, and awaiting suitable timings to meet the third. I have not sent anyone the invite using the application page. I want them to be comfortable writing the recommender essays first. It helps that all my three recommenders have not only been my superiors, but also my mentors, so they know me well.
Sent them the following documents:
Two essays describing the School and the type of candidates they seek.
My resume
The recommender questions
A deadline that is 20 days prior to actual deadline
Highlighted Copies of the essays
I'd advise giving your recommenders all information you can give them, without drowning them in numbers. Arrange a few meetings, and make sure they sound enthusiastic enough in their text.
Good Luck.