I rigged an adjacent tree a safe distance from Delaney's fragile perch and began the climb just as twilight evaporated into night. Unfortunately I didn't have my head lamp with me so I was climbing and traversing over to Delaney by the light of distant street lights and a couple of feeble flashlight beams from below. This is also the reason that there is no video of the rescue :(
Fortunately, the rest of the tree was healthy and the there was a branch above Delaney that I could use to position myself above her. I didn't dare put any weight on her branch for fear that it would break. Just as I was nearing a critical point in the dark rescue, a bright beam of light burst forth from below illuminating the way like a divinely sent beacon. It turned out that Enrique, Delaney's abuelo, had repurposed an indoor lamp, attached it to a long extension cord, removed the lamp shade, and replaced the 60 watt bulb with an outdoor flood light!
I was able to pick Delaney off her precarious perch without putting any weight on the dead branch, and after a few minutes of necessary rope management, I had her safely down to the ground in the rescue bag. The short video below was taken as Delaney scarfed down a whole can of her favorite cat food - quite a feat for a 4 pound cat to eat a whole can of food!