I had a question regarding the H-bridge we are using - DRV8837. When operating the part in a full bridge configuration, do you recommend adding external flyback diodes? Inside the part each FET has its own flyback diode, but I have heard that internal flybacks should not be trusted, or do not provide as much protection as external diodes. I am also not sure if the OCP (over current protection) circuit inside the chip isolates the diodes from being beneficial in the full bridge configuration.
In addition to continuing to evaluate the DRV8837, I would consider a similar full-bridge part if you have one with very similar specs.
