None, whatsoever 
I remembered something from a magazine from before Y2K.
Answers
- No idea; what type of options are there? You only need two wires (gnd and signal) as shown in the image. I think that in my house they have used reed contacts for the switches and magnets.
- In theory one zone requires just R1 and R2 and multiple switches can be connected.
- For the signals, any type of cable with two conductors should do.
Be aware that long wires might pick up noise and can trigger false alarms.
Regarding the PIR sensor, the answer is probably that the above will not work without additional components; the reason is that the output of a PIR sensor (to my knowledge) can drive both HIGH and LOW and you will need an open collector output. Below extension to the previous schematic shows the idea; a switch and the transistor in parallel (for one zone).
