1865

I was wondering what implications it would have had, if the main Confederate armies still in the field in 1865 would not have more or less voluntarily surrendered as in OTL but got beaten into submission by means of a final battle. Here are three scenarios I could imagine how this could happen...

Title, what if during Lincoln's murder and attempted killings of Seward and Johnson, Johnson also dies? What happens next? Does Seward become president?

*The carriage breaks down and they have to go another day *Grant accepts the invitation and goes with the Lincolns * Booth gets drunk and fails to kill Lincoln * Lincoln leans forward before Booth shots him * Booth is caught by Rathbone before he kills Lincoln * Johnson is assassinated as well *...