io domain by removing the Snackeet reference on the page? If someone were to enter that domain, they would see the "Return to Snackeet" reference and link on the 404 page.

Even with a custom CNAME, like example.mydomain.com/slug1, a person can find out the Snackeet reference if they were to mistype 'slug1'.
And with only the custom CNAME without a slug like example.mydomain.com, entering a random slug after the url would have the same effect, as it still gets redirected to the 404 page with the Snackeet reference.