Messenger channel profile in postback

I would like to send a greetings message in with a v12.1.2 based messenger bot that says
“Hello [name], welcome to our page.”

My Facebook app is still in dev-mode, and the user first and last name doesn’t seem to be sent at all, is that correct? Once the Facebook app goes live, the bot will receive the first and last names?

How then to refer to the user by name in the greetings and anywhere is needed?

I am starting to think that the problem is that the transmission from the Facebook servers is missing the user’s name, otherwise it would be available in the in response message to the initial payload.

Did you find a solution about this? I want to do the same thing but I don’t know where to start. Maybe @PierreSnell can help?