Sorry to be blunt, but let's assume she was indeed there.
If alone, is there a risk of self-harm without being seen (i.e. on camera), or can we almost certainly rule that scenario out as it probably would have been caught on camera?
Can we assume if she (alone or with a companion) was there, they will find footage proving she/ they were there?
I guess I am hoping that this area is different from the cases where there isn't really camera footage of the area or the cameras have been known to miss a person who was indeed there.
If she was in fact ON Goat Island a camera picked her up crossing onto it. If she was concealed in an unknown vehicle or had a hood up or something like that it would prob be very hard to find her. There are cameras at the falls yes...all over...but to say with 100% certainty they would have captured her if she went in is impossible. You would be surprised how many people go over each year without it being known. The upper part of the park and Theee Sisters Island is where the water appears to be calm but is not and it is much less populated than the part where the falls are visible. And at this time of night, if you really were determined, it would be very easy to avoid the cameras once on the island