Agreed, the no foiling to windward seems to be the consensus.
Most likely they are canting the lee board for sailing off the wind, which when combined with the wing tip or "L" gives the enough vertical lift to fully foil. Their speed may or may not increase, and their angle downwind may improve. Some speculation says both speed and angle will improve from foiling.
They are limited in the number of 72 dagger boards that they are allowed to make, but they can make as many SL33 or ac 45 dagger boards as they want to help figure this new development out. Mr. Melvin is on the design team for NZ so it makes sense for them to use the 33 as a test platform. Atrtemis focused on the big wing first and don't appear to be in agreement that fully foiling is the way to go.
the original mockup of the 72s showed banana boards, but i imagine that they work better on small cats that are crew weight trimmed, and big tris that have a regular board in the center hull. once they tried "L" and "T" foils they didn't look back.
can you imagine flying into the leeward gate at 40 knts., having to round up and crank the daggerboard to a de-canted position? what a learning curve this contest must have.
On the jibes it seems like they would set the new board before the jibe, but when 17 capsized going into their jibe they still had the 1 board up. if it had been down maybe both hulls would have been clear of the water and nosing in would not have been an issue.