Cirrus
I think you underestimate the difficulties here. Maintaining an exact height in the high hover in open ground is spectacularly difficult. The SAR boys, who practice that sort of manoeuvre all the time (as a means to avoid re-inflating a collapsed parachute canopy), keep the winchman at constant height above ground by continuous small adjustments on the hoist. Trying to do it just by voice marshalling to the pilot is virtually certain to result in the winchman touching down at some unintended point at some stage in the process. Now that's mostly OK in a peacetime SAR scenario. In a minefield it's likely to get you one more casualty. Even deploying just the rope and a strop for people to self-rescue into is fraught with risk of detonating another mine as the strop drags across the ground. And the idea of setting up a precision hover at about 200 ft for an extended period in a hostile area strikes me as tactically unsound ie you are likely to get shot down. Now it may be that in the circumstances that risk had to be taken, as I understand our American colleagues did in the end - and all credit to them. But that doesn't make it a good idea, just the least worst option.
Incidentally, I simply do not believe that downwash of itself can set off an anti-personnel mine. Debris blown onto a mine, possibly.
Sven