Also, according to Apple engineers, doing anything to any Preferences plist file directly - like editing it or deleting it - will not work as of 10.9 (and was unlikely to work before that.) It's just the persistent storage for the actual data that's kept in memory. The 'defaults' tool changes that data which then gets pushed to disk at some point in the future.

Think of it as editing a vmx file for an open VM - the vmx doesn't know about the changes and will overwrite it with the in-memory data.

(I have no idea why I have different fonts here!)

Double-clicking the virtual machine's file itself (the .vmwarevm file) causes Fusion to start, and the VM to start with it.

Double-clicking a VM in the Finder tells Fusion to open it and power on; it has nothing to do with autostart.

Auto start does not work in full screen but does on single window.

That's strange. In your System Prefs > General, do you have "Close windows when quitting" on or off, and if on, do you have your VM windows open or closed when you quit?