The work has been completed. The feedline feeding the scanner was picking up some ingress from my HF and 2m antennas, so I replaced the feedlines. My HF Dipole is fed by RG-8X (replaced RG-58) now, my 2M/440 antenna fed by LMR-400 (and in the portions that run parallel to the scanner LMR-600) which replaced RG-58 and the scanner is fed from a split from my TV antenna -- which is now fed by quad shield RG-6 (100%).
The feedline runs are about 150 feet of coax, and already I've noticed there is practically 0 ingress from my other rigs after replacing the cable.