In all those diagrams, it shows the beams perpendicular to the water.

Are we discussing the difficulties associated with getting the boat past this point?

Last I checked when we were over, the beams were actually past 90 degrees to the water, since the tip of the mast was in the water.... Is this perpendicular point that which the greatest torque/force must be applied to continue the righting of the boat, since the sail/mast is out of the water (and applying the greatest resistance to your rotational effort)?

Anecdotal evidence in my own personal experience, getting the main clear of the water was the hardest part. Once the water was off the sail it seemed to go vertical much more easily.

And how would standing on the tip of the lower daggarboard change the force/torque diagram?

With or without (like I was just standing on the board) the righting line being applied?