You can trade torque for speed basically. So yes. "Give me a lever long enough and a fulcrum on which to place it, and I shall move the world". That being said it would be so slow that you'd probably break something before you've moved a millimeter.

The same Youtube channel demonstrates how to use gear reduction to increase torque and bend a steel bar with legos: https://www.youtube.com/watch?v=jRn5waE0qfk

Yes. it would be equivalent to Archimedes’ claim “Give me a place to stand on, and I will move the Earth” (https://en.wikipedia.org/wiki/Archimedes#The_Lever)

Certainly. It would just happen arbitrarily slowly. (And, at that scale, other factors would come into play; the soil would deform under the wheels of the tank before it moved any distance, probably)