Regarding the one wheel pirouette these are the wheel chocks I used, one front and one back. I notice Harbor Freight sells an even bigger size one but not sure it will fit..
Even with our sloped driveway the car shifted a little when lifted on one of the sides but I felt comfortable as I was not getting underneath.....
Wheel chocks will stop front to back movement but I don't think they would necessarily help in a situation with two jacks if one of them fails, because there could be sideways motion that the chocks on the one wheel that is remaining on the ground would be unable to stop.
Using only one jack the car will always fall straight down if the jack fails. For example if jacking from the rear center, if the jack fails the rear will drop straight down. There could in theory be a tendency for it to roll forward or backward as it falls but the front wheel chocks should keep that from happening. Lifting from one of the side jacking points is similar, if the jack fails the car will fall straight down.
However if using two jacks, one in the rear and one up front on one side, with only one tire remaining on the ground, if one jack fails, as that side of the car comes down there will possibly be a sideways motion to the car which could cause the other jack to tip over. If the car comes down with a sideways motion that would be very dangerous for anyone nearby even if they are not directly underneath the car.
How likely is this? I don't know. But it seems better to eliminate the possibility of an accident by using a safer method even if it takes longer.
I still think the best solution might be to use wood blocks as I suggested earlier. Since you probably wouldn't need to raise the front end a whole lot to get the jack under there you could probably make a simple platform by laying out a thick piece of plywood or several pieces of 2x4 lumber under each tire, and add more layers if needed to get it as high as you need it. Of course you need to jack up the front tires to get the platforms setup underneath them, you would do this by jacking up each front side one at a time.
With both front tires now resting on the wood platforms you can now lift the front of the car using the front center lifting point, that will allow you to place jack stands at the side lift points. Then lower the car onto the jack stands. You could probably leave the wood platforms in place underneath the tires as long as the tires don't come back down onto them when you lower the front end onto the jack stands. If they do you might have to remove one or more layers of the platform. Once the front end is sitting on jack stands then you can lift the back of the car and place jack stands in the rear.
To bring the car back down do all of this in reverse. Lift the rear and remove the jack stands. Then lift the front of the car from the center lift point and remove the jack stands, and put the wood platforms back into place if you had to remove them earlier. Then lower the front wheels onto the wood platforms. Then lift each front side one at a time to remove the wood platforms. It's a lot of steps but it should be a safer way to do it.