Can't get rid of the hum- usual solutions not working

A correct analysus of what you have there shows that it isn't actually hum - it's bursts of full spectrum noise repeated at 60Hz intervals (which is why it sounds like hum), but those bursts occupy the entire audio spectrum. They look like this (I've put a red ring around one of them):

In principle you should be able to create a sound removal pattern for them, but in practice you can't because a single cycle of this is far too short to be used as a pattern, whatever you do with the FFT setting. If you use a larger sample, you end up including speech wherever the effect is applied, and that's what puts the artifacts in.

On a very short section of this, just to prove it was possible to remove it without artifacts, I highlighted individual spikes and applied Auto Heal to them. This works quite well, but I'm not aware that there's any way to automate this. You can assign a keystroke to it, but you still have to select each spike manually. It's a bit frustrating - there's a workable cure for this, but no way of applying it sensibly! 

But this is why no amount of hum reduction, or any amount of playing with harmonics or noise reduction will work. Specifically, the noise reduction and sound removal won't work because you can't use a sample that short, and the harmonic filtering won't, because there are no harmonics - just bursts of noise.