For CMRR and PSRR, you can do this with an xf (Transfer Function) analysis available in Spectre.

Set up your testbench sources for the supplies (of course), but also a source representing the common mode voltage.

Then run an xf analysis and tell it where the output of the circuit.

You can then plot the transfer function from every source to the differential output of the circuit.

Use calculator or an expression to plot CMRR=20*log(VDM/VCM) in the log-domain