Enhanced Surveillance

• WWizards of the Coast2018-10-05
  Official Ruling
  Enhanced Surveillance's last ability can be activated only while it's on the battlefield.
• WWizards of the Coast2018-10-05
  Official Ruling
  If you control a second Enhanced Surveillance, their effects both apply and you may look at an additional four cards. If you control a third, may look at an additional six cards, and so on.
• WWizards of the Coast2018-10-05
  Official Ruling
  The additional cards you look at due to Enhanced Surveillance's ability are part of what you surveil. You may put those cards into your graveyard or back on top in any order along with the others.

Rulings via Scryfall