The extend DVD films are still cannon in my mind.
This guy is funny...
If it's the director's vision for the film, then it's cannon.
The problem with this statement is that the Alien Director's Cut and the Alien 3 Special Edition AND the Alien Resurrection Special Edition are NOT the director's visions. Scott and Jeunet have both said that they prefer the theatrical cuts, Scott even said that "Director's Cut" label was just some marketing tool they came up with. And Fincher wasn't involved in compiling the Alien 3 SE, ultimately.
So really, by your logic, ONLY the Aliens SE should be cannon. No others.