I found the relays and isolators. They are in the same box with the clear cover. The box can be found above the radiator and air cleaner slightly off to the driver's side of the coach. That's where it is on our 2018 Bay Star anyway and probably all late model gassers. I might have to remove the air cleaner to make life easier but maybe not.
In any case, I've attached an image of what I found:
Seems to me I can just replace the BIRD controller, the black box and plug in the four leads to the new isolator. Then I can remove the battery leads from the relay and attach to the new isolator as well. Everything else will stay as is since it appears those disconnects are used for other purposes and are probably superfluous to battery charging.
I'll probably run this by Newmar before I do it. Worst case, is I have to wire in jumpers from the BIRD controller to the new isolator in order to keep the wires connected to the BIRD. I doubt it since the BIRD controller documentation says it is only for battery isolation and not disconnecting them but who knows.
We'll see! In any case, I'll document it for posterity. I'm sure I'm not the only Newmar owner that is upgrading to Battle Borns.