I have seen a game using only this timeline puzzle concept. I myself have implemented in one of my games, so what kind say... brilliant idea! :D
As a tip. Whenever you have to present some text that you want to "keep appearing", put the text you wont want to show with a transparent color, something like: "this is the text[color="00000000"]this is the part that will be shown later[/color]". (I dont remember the exact way to do this in unity, but they have a way, I have done it before). In this way when you show the text it will not "jump the line".