That's a good question! Were there rope fibers found on edge of right door where the rope would have made contact had the right door been closed when RZ went over balcony? If there weren't any, well, that surely would mean someone else closed the door AFTER she went over and if it wasn't LE who closed the door then it had to be the murderer!
Regarding the rope sliding across the balcony railing to create 9 inches of dust, well, from pic #3 on
http://www.thehinkymeter.com/2011/09/14/rebecca-zahau-case-the-geometry-in-rebeccas-fall/ there is a gap with multiple clearings of dust from E to F to the final resting place of the rope which is unmarked in the pic but I shall call "Z". This gap of dust clearings appear consistent with the rope having skipped (rather than slide) many times across the railing when RZ's body went over, and the rope, once taut, her body then bounced around until the rope from her neck to bedpost re-aligned itself in accordance with gravity and forces exerted by bedpost to position Z.
Since the final position looks to be right around midline of balcony and midline between the two doors, that appears to fit with the right door having been closed at time of her death. However, I'd like to have forensics assert that they found fibers consistent with the hanging rope along the edge of the door to confirm that indeed the right door had been shut when she went over railing.
Here's a question I have. Looking at same pic#3, there are two relatively large, dust-free gaps at A and D only. To me, these gaps are consistent with someone having been thrown over from their side, with RZ's left thigh scraping against gap A and with her knee bent, her left foot scraping against gap D.
I'm curious to know whether forensics found dust on the outer edge of her left foot. I think if they did, this would be one clincher that someone else had thrown RZ over the balcony - because there is no physical way could she have jumped from her right tippy-toes to a full sideways position over the balcony railing.