@Fore, as regards the electrical noise, in the electrical industry that is caused by singing components; normally capacitors. I have a mouse next to me with solid-state capacitors [SMT] which "sings" all of it's electrical activity, including radio activity.
Similar can happen with the inner ear itself, and classical tinnitus; although I personally find that entities cause loud pure notes more often than not. Given the type of hardware we are looking at, I would not be surprised if it caused the widespread generation of electrical noise; from natural sources and otherwise. I've also noted that tinnitus will change depending on exterior stimuli, so other entities will make it sound "different" too.
Now, a point, that singing is from a system where a charged field exists on one side, and an insulator prevents the charge from moving to its destination efficiently. When the capacitor reaches full charge, it will discharge. I can imagine large flying systems where this effect occurs, and creates a "singing" field around itself due to extreme electrical disturbance. Depending on size, I would expect this to get very loud, loud enough for the events in both videos.
Note: The events in the first video strike me as an area which has been "opened", and is subject to gravitational distortion between the top and the bottom of the opened area. The descending phenomena is it closing; a lid coming down.
I would suggest something was moving through the area, entered the area of distortion, "left", and the entrance closed behind it some time later. The electrical noise could be caused by the movement of charged ions through the air, and the effects of capacitance as well, all due to incredibly energetic local physics.
P.S: Keep going with breadcrumbs I find it "inspiring", and that clearly disturbs certain groups.