Great write-up and video, glad everything turned out positive, and that the folks will be okay.
I'm surprised to hear that more comm'l flights aren't routinely monitoring 121.5 MHz. Even so, being in the bottom of a canyon using a line-of-sight, low power (probably 5W) handheld radio likely limited your range quite a bit. Amazing you were able to reach a flight and have everything handed off so well. Kudos!