Did you restart Home Assistant between adding the files to custom_components and adding the lines to your configuration? If not, Home Assistant hasn’t loaded the custom component files which is why the config check can’t find them.
One thing to keep in mind is that by overriding all of the ring files you’re not getting any upstream changes to the ring component. This may be good or bad. If upstream ring changes cause the ring light component to break then it might be better to override everything. However, if upstream ring changes are implemented due to changes in ring API, etc., not getting these updates could cause everything with ring to break. I personally just put the light.py in config/custom_components/ring_light and in my configuration.yaml I have platform: ring_light.