180 degrees out of phase with one another. This produces a dynamically balanced crankshaft that has no desire to rotate about its midpoint. If spun in space it would exhibit no tendency to wobble. Therefore this bending does not seriously contribute to fatigue failure of the crank. The magnitude of bending, not its direction, is all that changes as the engine is run.
Moments are just the distance from a certain point at which a force acts.
These forces are equal for both crankpins as well as being in opposite directions. Because they are equal in magnitude and because their direction vectors are 180 degrees opposite they are considered balanced for force. In other words, there should be no net movement and no resulting vibration. There is a torsional couple because the connecting rods are displaced along the crankshaft. Therefore they create a couple which tries to rotate the top half of the crankshaft clockwise.