The answer to you 2nd question. I dot think so I have installed Suse with the PNP OS on. All my hardware except the modem was auto detected. Anyway my modem is a cheap windmoden, i dont even use it so who cares.
Coming to your 3rd question. I have a Gefroce3 working properly. Geforce 2 or Geforce 3 all use the same driver. The default XFree86 deriver is "nv" it does not support 3d accl. But Suse installer will tell you to install the "nvidia" ( this one has 3d accl) drivers and the kernel modules, and YaSt2 will do this for you.