An update: We've decided to go with 2" pipes throughout, both for solar as well as suction & pressure sides. In addition, we were able to find a local seller for 2" Fafco solar panels. The contractor agrees that it might be a bit of overkill on the pipe size, but that the improved flow rates should make several aspects of the pool run more efficiently (faster turn-over, better heating, better filtering), especially with a 2-speed pump.
Thanks again for the input!