Can you landscape to create shade over some of the water to minimize evaporation? Good thinking on the part of the contractor. All of the concepts are the same from aquarium to pond. It's still all about creating a situation so you ALWAYS have acceptable oxygen levels. The water temperatures will likely not be a problem if you choose the right fish. I'd think about redear sunfish as well. They are very tolerant of warmer water and grow larger than bluegill.

One strong consideration would be have the contractor design the pond so that you could seine it once or twice a year. This is the best management tool ever invented. This way you wouldn't have to manage entirely by angling, which will make your fish hook smart. I honestly think that in a pond your size that structure is overrated. Structure is primarily to make fish concentrate in an area for angling. You won't have this problem because you'll be able to cast to all areas of the pond. Less structure means easier seining. You can manage the livin' daylight out of a pond with a seine.

Bogs are good.

Holding a redear sunfish is like running with scissors.