About custom stuff

I have a few questions:

  1. Where can I see the ID of the tokens to replace them with custom art?
  2. Is the only custom stuff your opponent can see the sleeves and the mat?
  3. As far as I know, your opponent can only see them if you´re VIP, do you still need to follow the pegi-13 restriccion if you aren´t VIP then?
    Thank you in advance