As a matter of fact, to add on this, I am writing my own story right now. You can't just decide on the course of action or fate of the characters loosely, it's a constant back and forth process. Should F confess to B early on, or have some drama in between? Should A be evil, and if so, how much so? Redeemable or a complete ass? Who should find out their evil deeds, F? Someone else? Should S have the solution to this specific problem, or should M be the saviour? Should F or B die? One, both, none? Etc. I have actually written and sometimes even illustrated some of these scenarios, have fleshed them out but sometimes you just.. don't like it anymore, or notice it won't fit. So just like that you just scrap everything and try another approach. Once you do settle for a course of action, literally every single other thing you had in mind is now non-canon because it didn't happen and won't happen. You've made a choice and all those other branches become completely irrelevant to the progression of your characters and story, and shouldn't be considered canon or as if they mater when discussing things.