I second the raw feeding.
I had a foster who was bounced for many of the same issues that you describe. He was kibble fed, and the owners refused to try anything else, because "their other greyhound did just fine on kibble". I tried to explain to them that like people, not all food are suitable for all dogs---there could be issues with allergens, etc., but they wouldn't have a bar of it. They just thought he was being "difficult".
After a few days of raw feeding, he was like a different dog. His urinary issues cleared, up his poop was just the right consistency, his coat was beautiful, and he was bright and happy.
Maybe you could try raw feeding Sage for a few weeks and see how she goes?
ETA: Sounds like Ol' "Mud-Butt" might benefit from raw feeding too