Re: 0-ohm resistor
I'm usually using 0 Ohm device to enable some function on the board, then with a single PCB I can achieve several different function simply by set the right 0 Ohm resistor, from this point of view a 0 Ohm resistor act like a simple jumper.
Just take care about the maximum current that a 0 Ohm is able to carry on (this depend on the technology and the size), 0 Ohm isn't a shunt or fuse.
Also a 0 Ohm can be used to keep simpler your PCB routing.
Cheers
F.F. a.k.a. Powermos