An Order Of The Objectives

Well you could have a script dedicated to just storing a bunch of public bools. Then put those bools in an array or a list-kind-of-format and script it to say:

 if(bool1 == true)
 {
      if(bool2 == true)
      {
           if(bool3 == true) //... etc etc
      }
 }

This will mean that the last bool in the list/array can only be true if the one before it was true, which can only be true if the one before it was true, and so on. This would create an objective based system that would basically be like a checklist, where each box has to be ticked off in order, for the objective to be completed.

You can reference the bool-dedicated script in all of the scripts for completing individual tasks, and set the correct bools to true for each specific task. Hope this gives you something to start off with. @ockyboo