When I start a new Pi, it shows the cameras in order of added, camera-1.conf to camera-x.conf, and even if I delete a camera it adds as the next camera (camera-x+1).
If I start modifying and changing the order, it can (or did) cause problems for me.
Probably a good idea to turn off stream_localhost off in motion since motionEyeOS doesn't have a GUI to view, but on another OS with motion/motionEye it can be viewed locally so could be set to localhost only. I've done that, then enabled VNC to be more secure. Can only view on local console or VNC connection, no 'streaming'...