Unfortunately, the screw that is used to attach the earcup is one that is out of production (BISS2 is the reference number, see attached). You might be able to bodge together something with an M2 bolt, unless you can find someone that has spare screws they are willing to part with.
I have modeled the screws in CAD and was looking for a machine shop to help me prototype them for cheap/free.
For the headband pad, you can use the one that the TH900 uses, it's a drop in replacement. It is part # 1466441004