Hello,
First off all, let us try to clarify a few things:
#1: FreeMASTER supports direct communication over JTAG (without any other stack/driver/overhead) only for 56F8xxx. For any other targets, the communication with the host is done via BDM/EOnCE plugins. Basically, your target application (S32K144 in this case) must be linked with the Serial Driver that needs to run on your target.

#2: You need an external debug probe that supports the JTAG/BDM protocol like a P&E Multilink.
Are you fine with these constraints ?
Hope these clarify your concerns!
Best regards,
Daniel