Yes, it is possible to read a 4-wire PT100 RTD using the LabJack U6-Pro, and doing so in LabVIEW is a great choice.
Hardware Setup & Connection
To measure a 4-wire RTD, you need to supply excitation, and connect the analog readings.
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Excitation Option 1 - Current: You can either use one of the U6's current sources. For this setup no additional circuitry is needed.
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Excitation Option 2 - Voltage: A stable voltage can be supplied and a resistor can be used to create a half bridge. Both of those can be provided by the LJTick-Resistance module.
With a 4-wire configuration, you eliminate error caused by lead-wire resistance because the current is supplied on two wires, while the voltage is sensed across the other two using high-impedance analog inputs. Connect the two voltage-sensing leads of the RTD to a differential analog input pair on the U6-Pro (for example, AIN0 and AIN1). Utilizing a differential measurement helps reject common-mode noise and errors caused by the excitation current.
Software & LabVIEW Implementation
When customers ask which language is best for working with our hardware, we always emphasize that our API can be used from just about any language and the "best" language is simply the one you are already familiar with! LabVIEW is an excellent, well-supported choice.
Whenever you need to write your own application, we highly recommend that you leverage our pre-written code resources rather than starting from scratch. LabJack provides many examples to get you up and running quickly.
You can find our extensive library of LabVIEW examples and starting code here:
LabJack LJM Example Code for T-Series and UD Devices
For more detail, check our our RTD app-note: https://support.labjack.com/docs/rtds-app-note
