They have already shown that they are capable of operating a Shenzhou spacecraft remotely from the ground and docking it to a Tiangong module. To make a Progress-type craft out of it is largely a matter of giving it the necessary internal fittings for fuel, water, and coolant tanks and transfer. I don't know if Tiangong 1 has the external connectors for such transfer, or whether that is planned for a later model. I do hope though that Tiangong 2 or 3 will be continuously inhabited with dual docking ports, resupplies, and "visiting expeditions" (i.e. short time visiting crews in addition to the regular longer-term ones) similar to how the last two Salyut stations achieved.