Single Ground Buss?? Question clarified I hope

Reworking my DG 400 electrical system. Adding 2 batteries for instruments only and keeping main batts for motor related electronics and starter.

I have removed all of the positive wires supplying the breakers that are not motor related. At present there is one main ground buss.

Some of the instruments already have breakers and positive wires (original and in bundles) from the breaker to the instrument and negative (also in bundles) to the ground buss. I have left these in place. I will run new positive wires from a new positive buss to supply the breakers, and also other instruments.

Would I create any problem using this common ground buss for the motor related electronics, AND for the instruments which will be supplied by the 2 new batteries which are a different chemistry?(LiFePo4) The ship's chemistry is lead acid.

So the main question is DOES USING THE SAME GROUND BUSS FOR BOTH SYSTEMS CAUSE ANY POTENTIAL PROBLEMS?

A couple of people I respect have said it would be ok, but I'm looking for any potential issues.

I will be using two separate switches for the new batteries that are pull to unlock SPST.

Thanks

Kevin
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