Driver two motors with same driver
It is fine to drive two motors in parallel on the same output stage as long as they have the same resonance frequency. So if you use motors (same size) and from the same batch and you should be ok, since the frequencies are very close. Motor produced on two different batches of PCBs will have different resonances, since the thickness of the PCB will vary.
The output stage should still be tuned to approx 45 kHz