The dark streak being pointed at by the arrow is the bottom edge of the open door.
The window nearest the tail of the aircraft is ABOVE the line that contains the rego number. That's what your red arrow is pointing to, THE WINDOW.
Then there's the open door, which isn't anywhere near up as high as it appears to be in an earlier frame which was shot FROM BELOW at a different angle.
The remaining two windows, you can see the frames, but the waves are obstructing your view of the glass. It's just my humble opinion...
You nailed it.
And further proof of that is the shadow that the open door is casting diagonally across the top of the plane.
Which means they are the same planes.
Thanks tomcat.