How move 1 existing, active Safari page to Display2?

Yes, right.

And now any front window can be moved easily to another display (here: D2)

With:

Move and Resize Front Window (2259, -148, 1458, 1100) ***

  • the front window

  • in Front Application

*** These values are case-specific and were culled from Chris Stone's Window Information Tools - Macro Library