Yes, it will work, just charge more slowly.If we use the hub with a lower watt charger apart from taking longer will it be able to cope? Say a 20watt will it work?
That's the beauty of PD... it's an active protocol with a microcontroller in both the source and the sink. Upon connection literally the two dedicated microcontrollers talk to each other. the sink asking "what are you capable of" and then requests a voltage and limits current draw based on the source capability.