as i say, throttle position, water temp and air temp are relatively easy as you can use any universal logger with 0-5 or 0-10V analogue inputs.

don't know about the rpm (guess you need a converter to convert pulse at coil or from crank position sensor to voltage).

don't know how to do ignition timing either.

what do you mean by fuel? you want to somehow know the duration of the injectors?

i don't know if it's possible to intercept these signals easily somewhere on the mainboard? would be interesting to find out.