I was mostly though writing a long answer, but the simple answer is that the data from your customer is incomplete. Those files do not even contain data on which parts are on a PCB. For that you need the placement file, and the placement file also has the locations and orientation of the parts.
It is also not really a KiCad question. Going from computer data to real manufacturing, is where KiCad ends, and specialized software for this task is used. Cam350 is a name of such software that pops up on this forum sometimes, but I have no experience with it.
Yes indeed, and normally that data is provided by your customer. You can recreate it in KiCad but it is a bit of a cumbersome process: