Anyone know anything about disc brakes?

I believed the kevlar was there, as snottyotter suggested, to stop the cable bursting under load. I thought the linear strands kept the length constant.

It is, the Jagwire use the kevlar to hold the linear strands, whether Yokozuna use coiled outer to hold the linear strands (abet a lots stiffer).

Regarding pad alignment do you mean the pads not being parallel to the rotor? I had wondered about this. They do look to be off a very slightly.

Pads not aligned inside the calipers, every once in a while I build up a bike whose pads simply doesn't sit straight inside, BB5/7 were notorious for this issues in the past which is why people have poor experiences with them.

Shimano, TRP, etc. are not without problem.