Zygi,
Very keen observations. I tried to follow the plans as closely as possible, but also took some recommendations from the box builder/shop owner who was helping me. I am not trying to argue here, I just wanted to state my reasoning behind various construction decisions.
*On page 4 of the blueprints, 2 screws seem to go from the driver baffle into the wall making up the horn throat. So, wouldn't this be coupling the driver baffle to the wall of the horn throat?
*The cleat: based on the assumption that a friction fit is taking place between the cleat, the driver baffle and the horn throat wall, I would think that a substitute for the cleat would be reasonable. We elected to forego the cleat and instead, use two more bolts with lock washers and T-nuts. This way, the driver baffle is bolted to the horn throat wall panel. Time will tell if this was a wise decision.
*With regards to the mitre cut on the edge of the second fold with the velocity disc, I may have read the blueprints wrong. Page 4 of the prints has instructions to "soften edge". Looking from the top view of the prints on page 1, I think you are correct and I just plain botched this part. I chalk this one up to inexperience.

*We did include part F. Even I in my n00bness was able to recognize that the outer panel and horn throat panels needed to be braced. We were using a brad nailer for most everything and one of these started to split. When in doubt, add glue?

The build started out with high QC, patient cutting and dry-fitting. By the end of an 8-hour assembly/construction session, my meticulous nature began to be ruled by fatigue and impatience.
*Also, another error in the build occured with the placement of the internal anti-reflection baffles in the sealed chamber. If you look closely, you'll notice one of the vertical semi-cirlce discs is mounted closer to the driver baffle than the other. I am not sure if this will have a dramatic effect on the overall performance of the box. Obviously, symmetry is desired...we will see.
Thinking back, I wish I had more time. Because this is a project for an acoustics class, staying on schedule sometimes supercedes producing high-quality workpieces. I am certain this is not the last box I will build.
I am having a blast getting a crash-course in acoustics an applying that knowledge while building the WO32.
Above all, I appreciate the constructive criticism you have so courteously offered. I hope to gain as much knowledge as possible from all the audio oracles that frequent the forums.