So.
1. It worked for at least 20 minutes.
2. You ran Audessey and it broke.
3. A hard reset (which will take Audessey back to it's default config) didn't fix the problem.
4. As you add more loads (connects) to the HMDI circuit the noise gets worse.

Things are starting to point to a hardware failure in the Marantz. Maybe the power supply for the HDMI circuit is on the fritz and the more connects you hookup the worse it regulates.

Hope the new cables work. If not I think it's time to send the Marantz back.