Personally I think that a major contributer to the delam, is due to the sharp edges on the gear door cut outs. It is clear that the failure propagated from this area. My opinion is that the panel flutters slightly between the gear door cut out, and the bonded area behind. Glass fiber is a brittle material, and this is a typical case of a fatigue fracture failure. To prevent this I say cut the door opening as round and blended as possible, as per instructions. Never use sharp edged cutout on glass fiber, in fact any material, if it will be subjected to cyclic loads.
Pressurization is present in this situation, and the use of gear bay compartments would be a good idea. Cutting holes in the rear fuzz, will not in my opinion make much difference, apart from inducing a flow, and hence upsetting the airflow.

I would just like to comment on the construction of the hotspot, and say that in my opinion I think it is not sufficient for its purpose, and am surprised that there are not more failures. The hotspot is a great model, I have one, but due to pore design and construction of the fuzz I had to redesign the internal structure to satisfy myself, which inturn meant that the model talk a lot longer to make.