It works! Thanks everyone!
I left out the zener diode (because I didn't have one on hand) and instead put a 100k resistor after the gate to divide the voltage in half. It's on a battery anyway. There will be very little in the way of spiking and the battery would have to hit 40V for the Vgs to be 20v. You have bigger issues when that occurs. (rating of DC/DC supply exceeded, rating of pretty much everything in the drone exceeded, rating of caps and fet exceeded)
I have seen similar circuits like this on the internet, so I assume its also acceptable. Is there a reason for the zener method vs other ones? Or is the zener clamping method for situations where there is significant noise/ripple?
I had issues when I first put this back together actually, where it kept turning on! And then at the same time, wouldn't turn on. Somehow when the p-fet oxide layer blew up, it must have connected gate to source. (Which I suppose is a thing) and so my little diode was blown to bits, and the npn transistor was also shorted. So it kept turning it on, and not responding to the switch. Now that I've replaced pretty much this entire section, all is well. Hooked up to the scope and power supply set to 28V (way higher then the battery should be capable of) the gate of the fet only sees 14V and there are no captured spikes or dips in that higher or lower. Everything else seems okay. And now a short is impossible as the gate is isolated on each side by 100k resistors.
This is the new schematic, and the bodge. Works great!