There are 2 RPM solutions:
1. from injector signal, but only limited injectors are compatible (with clear PWM signal) and RPM will not work with no engine load (e.g. breaking with engine) because injectors are off
2. from hall signal (pulse signal)
I think that you have injectors with no clear PWM signal so you should use only solution 2. Any hall sensors will be fine (VSS sensor connected as RPM sensor will be also compatible). You can also use stock RPM signal - it's usually goes from ECU to instrument cluster. There is dedicated input in UTCOMP for RPM.
Answering for second part of question - fuel pressue as voltage in logs - yes it's correct, you can rescale it in excel e.g. pressure = a * voltage + b, where a and b are your sensors parameters.