Double tap, Longpress unfortunately these concepts do not exist in
There is an option in project settings that lets you emulate ScreenTouch as mouse events, you'll be wanting to enable that.
The preferably have an autoload to pool unhandled events
if event is InputEventScreenTouch:
new_event = InputEventMouseMotion.new()
new_event.position = event.position
As mentioned before the other conditions do not exist and you will have to code it on your lonesome