Automotive engineer here. One consideration for the diff motor is that it would REALLY sag the diff. I think the only way to go would be a front and rear generator/motor combo in one housing to replace the transmission, powering the rear end with a driveshaft. A direct drive clutch between the front and rear motor/generator would economize driving and assure high power at high speeds.
First, there's probably a pressure relief system already on the tank.
The problem is that is analogous to drilling a hole in a pressure cooker, it's either going to rupture the tank entirely, or blast the contents into the air.
Also curious where you would get a "quadcopter with a small drilling machine" with a couple hours' notice; even if you had one, it would be hard to maintain a position at one exact spot, and much of the lift energy would be expended in the torque reaction of the drill.
The only sane way unless you have not enough water to fill the tank. Oh wait, you can fill it with that solid water on the ground, as long as you give it a few hours to melt from the ambient heat in the house between each use.
The gear teeth are cut with a file. For the angularity, draw a circle with a compass and subdivide it by measuring linearly with a measuring tool. This can be done larger than the part, and the teeth locations marked with a straightedge. By cutting the teeth where marked, you avoid a stack-up of error.
Traditionally, lack of demand and the fact that GM was fastidious about keeping them off the road means that they would probably threaten a lawsuit. Electric cars in general have only become popular in the last 5-10 years; the lore of the EV1 has grown accordingly.
Copyright law for art and sculpture requires registration of each design; in searching the copyright records it appears that GM doesn't do this. Really the more appropriate forum would be to get a design patent but those last for only 15 years anyway.
Trademarks must be registered (and also apply to specific categories, though a kit car and production car are in the same category). Surprisngly, "EV1" is owned not by GM, but by Kia (the graphic is different). What this means is you can make the (GM) EV1 logo no problem, and also sell a kit car as something like "inspired by the GM EV1" but if you sell it as an "EV1" then Kia might come knocking.
In short, I don't see much getting in the way of making an EV1 kit car as long as you don't advertise it as a literal GM or EV1 car. Though as stated, you can include or sell separately an EV1 badge that buyers can slap on their own property without issue.
Already 90-95% get around without a car and the rest are paying. Car traffic is necessary to an extent. Compare how shipping companies offer Next Day Early AM shipping for 10x the cost of 4 day shipping. Hardly anyone uses it, but when you need it, you are glad to have that expensive option.
Steve Jobs did this, he got a new car every 6 months yet for years only drove a 911, then an MB SL55. Why have to learn a new car when you like what you drive?
Consider that any competent manager will value polite debate and constructive criticism far more than the empty words of "yes" men.
Guess which category "reasonable ... consideration and appreciation" falls into.
Put another way, if you read North Korean state media, you will find that they always have a reasonable level of consideration and appreciation for their government.
Occasionally I will "wash" dirty PCBs by spraying them with 50% ethanol, 50% water, then drying them with an air gun or the like to get the water off in a reasonable time.
Nearly any properly designed board will not hold residual voltage for long when disconnected from power, so the slight conductivity of tap water is a non-issue.
A more insightful question is "were they ever cool?" It's hard to think of any company or figure, before or after the Twitter purchase, where them gaining a blue check made them "cool", or even fractionally moreso.