I did something similar. Ran new rear locker air hose and four spliced-in wires up to the ABS tray where they reconnect to the connectors.
I didn't add an additional platform to the tray because there is space under the center area of the tray and it's decently protected. I drilled and shaped holes in the tray for the rubber compressor bushings. Then ran the breather tube up along the wiring harness.
View attachment 270354