[Lizard]

Both 1 and 2 have been developed to some degree and are discussed over in the OmniFocus Extras forum.

If you were hosting your PHP website on the Mac that's running OmniFocus, and if PHP can tell the system "Hey, run this file" then it could trigger an AppleScript. And the AppleScript library for OmniFocus can create actions in the inbox, edit the properties of actions, etc.