Seward Attack

[RJNorton]

Is there a major argument that Lincoln's April 11th speech was not the "trigger?" It seems to me that the plans changed after that speech. David Herold was sent into Charles County on April 13th (perhaps to alert the Confederate underground?). Powell began scouting Seward's home on about April 13th. And Atzerodt was told to get a room at the Kirkwood House.

Which happened first on April 11th? Lincoln's speech or Mary Surratt telling Lloyd to have the shooting irons ready? I think Lincoln's speech came later in the day(?), so I am wondering if kidnapping was still the plan until that speech.