Thanks for these steps, Colleen. What we’re referring to is the fact that in Step 1 you’re forced to choose Add New Wallpaper. There’s no way to edit or otherwise customize the existing default Lock Screen.
Similarly, when accessing the Customize options directly from the Lock Screen, clicking Customize below the default Lock Screen automatically brings up the Add New action—there’s no way to customize the existing default. I can’t change the time font, add widgets, etc. to my existing default Lock Screen.
To take advantage of the new Lock Screen features (specifically the customized font and widget options), I had to manually recreate my default Lock Screen (and Home Screen, since you can only save the preset pair or manually customize a new Home Screen to go with the newly-created Lock Screen).
Since there’s also no way to delete the default Lock Screen, I now have a defunct, duplicated default that I can’t remove.