>If the comment has at least one reply, then the username will become [deleted] (or [removed]), but the comment/content will remain.

That's false. Both the content and the username will be replaced by [deleted] if the user (or a mod) asked for the comment to be deleted, and it had at least 1 reply.

Here's a test I just did:

https://www.reddit.com/r/television+none/comments/88rd9e/net...