Due to how amish I am with basically any kind of scripting, I gotta ask for more clarification now.
I have these scripts that I want to use for all classes (key bindings and the null movement script etc.) but I don't know how or where to bloody put them.
Do I copy and paste each script into the class config files? Or does it have to do with this mystical autoexec file that I have no idea how to use properly?
A little bit of both, really. Scripts that are universal (read: not dependent on a specific class) should be put into the autoexec.cfg file. By default, this file does not exist, so you will have to create a file in Notepad and name it "autoexec.cfg" and place it in the proper folder. If you want to use a script that benefits every class in the same way (like a jump/crouch bind) or use something that will modify some of your gameplay (like Chris' FPS scripts) then they belong in autoexec. All binds placed in here will affect all classes, no matter what.
The individual class files are for specializing your binds for each class on their own. However, there's a slight catch to that one. Let's say that you want to bind the F key to be multi-purpose, depending on which class you're playing. For example, you could bind "last disguise used" as Spy to that key in the Spy.cfg, and a rocket jumping sequence (+jump, +crouch, +fire) as Soldier in the Soldier.cfg.. Both overloaded to the same F key. When you pick Spy, the config is loaded that way, and Soldier the other way. You still need to tell the other class-specific config files to do something with the F key whenever you're playing as one of the
other classes, otherwise your results when pressing that key will vary. (ie, you'll either do nothing since no other class uses disguises or jump/crouch/fire at the same time as someone that can't rocket jump, you see.) In that case, either bind F to something that will benefit that class or place "unbind F" in every other class config file.
Stabbystabby has a peculiar script that is designed to auto-reload the Ambassador, and turns it invisible once you fire the gun. (so the pesky reload isn't always in your face.) Now, you still would have to do counter-binds in the other class config files, otherwise your primary weapon will still turn invisible when you play other classes. The process is tedious, but worth it once you get each class to operate how you want.
You can modify all 10 of the config files while the game is open, but the changes won't be applied until you either type "reload autoexec.cfg" in the console or reload the entire game. Reloading autoexec will automatically refresh the class config files and their bind changes. Lots of tweaking and trial and error, but you still get a lot of flexibility in your bind customization if you put in the time to iron out the wrinkles.
Sorry if this description is confusing. Good luck.