The sound engine embedded in Polyphone should reproduce accurately the sound of the presets except for the modulators defined here:
https://www.polyphone.io/o/documentation…editor#doc_modulator (this has not been implemented yet).
You may check with FluidSynth (Swami is using it) if the vibrato is right, I consider this software as a reference.
If only the other sf2-player provides no vibrato, you may send them a bug report.