Have you guys ever seen the movie Spinal Tap where the band is playing and the Stonehenge set is being lowered to the stage, only it is ridiculously small compared to their expectations? The set guy got the scale all wrong.
That is what is going on here, you are the set guy, and your sense of scale is way off. These photos that the ROV took are taken from from say 1-3 ft away from the objects you are looking at. Any farther and the light becomes too diffuse to see. The strut you superimpose, would be maybe 6 inches long instead of the 6 ft you imagine it. If the object were 6 ft, the camera would have to be a good 20 ft away, and at that distance there simply wouldn't be enough light to light up the bottom. I don't know what the wattage of the lamp on the ROV is, but it isn't big enough to light up the bottom of the ocean from 20-30 ft away.
Given random pattern, and no scale, we can see all kinds of stuff in these photos, but I really think it is not a productive enterprise. If there were a real object there, like the rope, we'd recognize it immediately. Trying to find other stuff that is not obvious may be fun, but is similar to seeing bunnies in the clouds, everyone can see one if they look hard enough.
We went through this with images in the lagoon that people thought represented the Electra. We even went to some of the locations just to rule them out, an in every case where someone was sure they could see some sort of object, it wasn't there.
With the upcoming expedition, there will be plenty of images of real stuff to look at - keep in mind the NC wreckage needs to be surveyed to ensure that there isn't an Electra mixed up with that debris, so save your effort for reviewing that footage with a critical eye.
Andrew