Alright. The thread has been crawled by search engines already, though. 
I've taken the liberty of hiding the edit history on both of our posts, so the domain can't be seen there.
Keep in mind that Let's Encrypt certificates are all archived in public Certificate Transparency logs.
Great! 
I don't know. 
In theory, it would be safe. But in theory, it wouldn't have been broken in the first place!
You can give it a try. It may work fine. It may break the domain (with validating resolvers) until you turn it back on again.