I tried my trick for using heralds in Assassins Creed Brotherhood to remove Ezio from scenes and it worked (originally used in Assassins Creed 2)! There's some things you should know first. Heralds can only be bribed when you have at least half full notoriety. The game forces you to be incognito until sequence three, and even then there are other times you can't get any notoriety (such as the memories where you renovate the faction headquarters). The scenes recorded for this video are two scenes with Leonardo and some templar agents (for the other agents there weren't any heralds close enough to use). The basic setup is to steal from someone to get them to fight you and the herald will back away as a result. Use this to move the herald to where the scene will start. I've gone through part of the game and there are some scenes where using heralds doesn't appear to work, but hopefully there are more where it will.
Wow, Leonardo's age sure is getting to him...
Great video, by the way!