Hello Gary! You say:
"Edward would have had to ensure that his super magnets
were below the blocks at all times, to balance gravity
and lift them."
But, perhaps he used the 'power' to tilt a block,
chock it up, and then, direct the magnetic thrust
beneath it to lift and move it?
Or, could he have dug a pit below?
But, it's interestng to learn that tests have proven that gravity
influences may be cancelled 'out' when the correct magnetic
properties are brought to bear on an  object?
Maybe? we have discovered how he did it?
Did he build the; THE MOST POWERFUL ELECTROMAGNET
EVER CONCEIVED? And then use it to thrust, instead of
attract?           Ciao, Jim

P.S. We know, from using a compass, the earth's magnetism
does not attract, but detracts, or repels, thus with a strong
enough 'magnet' of 'like' influence, I believe the job of moving,
lifting, and placing the blocks would be a snap?
But it must be a very, very powerful device!