Hills A and B, with heavy pedaling in whatever low gear you need, will go with nearly anything. Basically, if you can pedal it, you can pedal up it with a tiny hub motor helping very little. Because you can gear all hub motor lower only by making the wheel diameter smaller, they will be running horribly inefficient, and heating up fast, and will overheat fast.
But not in 500 m. 8) Repeat that 500 m a few times, and bye by small hub motor.
At your projected weight, 250 pounds plus rider, means 400-450 pounds? Only the bigger hub motors are going to do that weight up hills C and D. They can do it because with 2000 watts or more of real world power flowing into them, they can maintain 15 mph, or close to it, up those hills. This means in your big wheel the rpm does not drop to the low efficiency range of the motors power curve. The rule of thumb with hub motors, is you need a short hill, or you need to keep your speed up them.
Keeping your speed up on a long hill, or mountain, or repeated short hills, is impossible with the smaller motors, because they just are not made for 2000w. Many can handle 1000w, so its quite possible to use two of them, one on each wheel. This is a proven thing that works.
So if you don't go mid drive, which does allow gearing changes as you ride, the only way to get low drag with the hubmotors off would be two geared type hub motors. Like two macs. Then you get both hubs freewheeling when off.
But many overlook a thing about the big direct drive motor. Yes, it will drag with the motor off, this drag varies with speed, and it varies motor to motor. But lets say you get the one with huge drag. Do the calculations on how much power you need to give it to eliminate the drag. Yes, it will drag with the motor off, but the tiniest trickle of power will eliminate the drag, and likely add a handful of watts assist. Lets just assume you have a setup with 5 levels of assist you can choose on the display. Level one will max out at about 75 watts, but you can ride using half throttle using 30w. Now, lets assume you have a larger battery, say 1000 watt hours. And you need 800 wh of it, to get up that hill. 200 wh left. 200 divided by 30 is 6.66 hours of ride time. Six hours of riding with just enough power to eliminate the drag of the hub motor. Plus perhaps an hour getting up that hill too. 7 or 8 hours of riding time a day enough? It should be.
So if you really need to power up those hills, the drag of a big ass direct drive motor is not really any penalty at all. This is part of why I did my touring with a big motor. I rode with assist the whole time, but used 2000w only to get over the mountain passes, and rode the rest on about 250w of power. The 250w was just enough to make my pedaling effort with all the gear and heavy bike and batteries feel like riding 15 mph on a regular bike. I was not up to pedaling no assist, because of an illness. But for you, all you need is 30-50w of power to make that drag go away.
With the big hub motor, you will maintain that 15 mph or so up the mountain, down it because the drag helps you slow on the descent, and continue at the same speed on the flat. Its a beautiful way to cruise. Speed stays same the whole time,,, think about it,,,, this means you never shift all day.
But like I said, if you want to get up those mountains on 700w of assist, it must be a mid drive. But even with the weight, your lowest gear on the one front ring you get will be plenty. You will want to choose the smaller of front rings you can have, but something like 42 tooth up front will be plenty with that much help. You simply won't be riding up those hills 3 mph. Just get a nice big low gear cog on your rear wheel, and you will have all the low gear you need with that mid drive helping.