How to remove camera shortcut on lock screen?
If you're looking to just eliminate its presence (but not the function), get Xposed framework and this module: LINK: Xposed repo. Not just the camera icon - everything you don't want on the lockscreen can be gone.



Also, many custom ROMs such as CM allow you to change where the shortcut goes. 



Here I change it to calculator:



All demos done on my own Nexus 6P.

Both require you to unlock and tinker with the phone; then again, what's the reason not to do it when you have a Nexus?