Yes you can go without the 4 conductor wiring. Usually the 2 extra wires will be different colours, such as red and green and the "regular" wqires will be black and white.

Having the series/parallel switching will definetly be a benefit if you play a wide range of music. On my Telecaster I have both pickups wired this way. It wouldn't cost much more to install because think about it; the other wires are already right there and the control cavity is gonna be opened up anyway. It will cost you more in parts than it will extra to install push/pull pots.