Don't take this the wrong way:
1: Email is real, I can forward you a copy of the email I have if you want. The picture is broken at the top because I wanted to have the screenshot show my question at the same time as the answer, But i don't know how to do that
2: I didn't ask about tournaments. You should read the whole thing.
3: Customer service from GamesWorkshop IS official. DO you need the owner of the company to personally sign it? How about the share holders. Customer Reps are official.
The only important question and answer that is in the email:
Does this PDF override the paper codex I just purchased for 30$?
The new PDF is up for the people who do not have access to buy the codex anymore.
I know that for our tournaments we will be using the Physical codex and NOT the PDF. I hope this helps!
I'm pretty sure that means that If i own the paper codex, I'll be using it in official GW events, which is basically what this whole thing is about.
I don't know how you can get more official then a GW employee, who's job it is to answer this kind of stuff, says so.