How to Reduce Serial Noise from a Refrigerator
Try any ideas that you mention. If you try one and it doesn't appear to work leave the idea implemented and try the next idea. Eventually you will arrive at a solution but it won't be ideal. To make it more ideal try removing one idea randomly to see if you still have the same fix. Repeat until you have removed as many potential fixes as possible but still have a good solution.

That's the approach I generally take.