Cubase do not "generate" sounds... I mean it is a sequencer, controlling external MIDI devices (MIDI modules, synthesizers, etc..). Even the VST synths are in a way external devices. Sound fonts ccan be loaded in a sampler, soundbank of your soundcard, and *some* synths. I don't think Reason uses them. It has a sampler module (NN-19) but I think you have to do your own patches/instruments. You can try though

Good luck