I’m not the WhatsApp specialist, because I hate that app.
From logical side. If you disallow any data usage for Whatsapp, it won’t get any access to his main server and you won’t get any messages. But this is the same if you will open the app.
As far as I know, the settings will prevent that others can see when you where online last time and the other point will prevent that others will see that you have read the message.
But as I have written, I’m not the whatsapp specialist