I have never tried it, but the 555s are designed for a Datejust case, which has a different profile than a 55xx Sub case. So I do not think they would fit properly. Whether they would fit at all, I cannot say. Unless someone else has tried it, you would need to try it yourself.
Depending on what you mean by 'crank down', you should never apply alot of torque when installing a caseback. Snug, using the appropriate tool, is all that is needed. Any tighter & you run the risk of damaging threads, warping the caseback, coming into contact with the movement or having difficulty removing it.
A number of Rolex initial production models in the 1950s and early 1960s were fitted with Brevet crowns (later production shifted over to the standard crowns)
As stated above, it is very difficult to successfully remove damage to a gloss dial. That said, I was able to remove the light, circular mark left on 1 of my Sub dials due to a hand that was installed too tightly using Meguiar's automotive plastic polish, followed by a bit of enhanced patination from a UV light. Of course, you must remove the dial from the movement before performing this work & there is no guarantee of the results. Best to experiment on a donor dial before attempting your main 1.
Pics are useless, 1 of the the marks of a scammer.
From what I can make out, it looks like the seconds hand has a squared tip, which is incorrect for a gen Rolex hand. I would pass.