I have tried a number of the same tweaks as you and found them beneficial. But the biggest impacts I have had are from the PPT Omega mats (treating the gear), and Synergistic Research products treating the room. So great and profound have been the changes that these "tweaks" have wrought that I would call the "tweaks" components in their own right. Sure the "system" functions without them, but it functions better with them. A lot better. A helluva lot better. My system with "tweaks" (ie the added components) performs better than any system I have ever heard in a retail store regardless of cost. I couldn't say that before I started "tweaking".
Looking at your list I see lots of treatment of your gear, but not much treating your room. I would suggest that is the next frontier for your pocket money. Investigate HFTs and FEQs, you won't be disappointed.
Nga mihi nui