Okay, I am honestly not being funny, but I do not understand what you are doing. Based on the OP, he wants to play a timeline based on the scene previous. So in your example, the idea is, when the user presses the button which takes him to a new scene, it then fires a timeline?
So if the user is on Scene 4, and clicks to visit Scene 2, how will the button know to play the timeline Scene 2, and if the user is on Scene 4 and wants to visit Scene 3, it would need to be a different button, unless he uses the Next / Previous option.
I have never used Custom Behaviours, probably because I have never needed them, but i do not understand the need for them in this instance, hence my questions. I am trying to learn the reason for them