The conundrum is for Boeing, not Airbus. Boeing could re-engine the 767 for freight and for its passengers hoping to snag a large Chinese order. That risk is too much for Boeing's canceled 767 passenger program. Boeing will not make two different 797 models, one for passengers only and another for passengers with a freight capacity. There is no solution for Boeing, in this case, it will build the passenger oval 797 hoping for at least two thousand orders while leaving the Asian market to an A-330 NEO like Airbus offering. Building a 787 light version for the 797 program is not advisable or should be considered unless copious numbers of orders exist for a 787 light version.
Extreme Oval Design With Freight
Russia's version came before the 797 concepts: Pictured below.
Boeing has the orders for a 797 start, but the number is way short of where it sees its financial targets before announcing. It probably has about 400 797 promises at this time but it would have to reach a thousand units committed before going all in on a 797 flying oval. It needs China in its battle with Airbus, Airbus needs China to save its widebody bottom end of the A-330/350 family. An A-360 or whatever is on the horizon from Airbus. The 797 was supposed to be a killer shot plugging the A-321 NEO. Instead, the game of aviation leapfrog will continue for both makers trading off model against the model for years to come.
A concluding sentiment is for Boeing. Build the 797 flying oval and well above its competition capability, Airbus. China does need to move passengers at this segment in time. The option for freight service by the 767 (i.e. FedEx, UPS) is well established.
China's freight needs will outgrow dual passenger level freight services almost immediately, and any other dual threat airplanes hauling both passengers and freight at the same time which will not serve its greater market but will only serve only in niche regions. The Gap airplane is not meant as a panacea for moving stuff but is meant for moving passengers up to 5,000 miles.