If I was going to source some original Hofner ones for mine you could've had my Schallers. I've realised though that the holes have been enlarged to fit the Schallers so no going back to original now without extra work. Hofner used Schaller parts when they ran out of stuff as Schaller was literally down the road so they're kind of fitting anyway.
I'm not sure about mixing colours of hardware, if anything will work though I'd say the tuners might as they're on a separate part of the bass, hard to say without seeing a mock up though.
Also on the pickup front, does it matter that the pickups are too wide? Presumably they'll be sat in cavities so the raised centre section of body is largely irrelevant, isn't it?