Remember if you use too high of heat during the process and/or cool incorrectly you run the risk of damaging any springs so be forewarned
Would not plate the trans york or driveline ends
Shock tower supports? Not sure why those are on the list if they are painted black
Pinion ........ what? Yoke. Again would not plate that.
Are you really going to disassemble the whole steering box? Would not be my choice
Of course your going to get different opinions and not all of these are plate the part and installed them items. Plating can add more work to the process than other methods in some cases.
Steering box mounting bolts (as well as the two for the idler). Are you using magnesium or zinc phosphate. Zinc may not get them dark enough to replicate heat treated cast steel
If your thinking of doing the idler - you know there are a number of different finishes used on the completed assemble and there are items pressed on/into that were added after that parts were made.
Someone on this site recommended phosphate an oil for my driveline ends and slip yoke.
Shock towers coming off the list. I added them with a question mark because someone mentioned he phosphated his but I think it was from a later car.
My steering box has been rebuilt by Lares Corporation. However my three mounting bolts are needing some attention. Are those phosphate and oil?
Copy on the idler arm. Will need to research more.
I am using manganese parkerizing / phosphating concentrate Charcoal from Palmetto ENterprises