I bought the Marelon replacements and started the work. The first one I tackled was the overboard discharge (it looked the worst) and it didn't come out easy, so I cut it off with a cutting wheel and then cut the nut so it could be spread open. That was easy.

The good news is the cut cross-section shows the metal was 100% pristine with no signs of electrolysis or discoloration. I won't replace the rest of them. They lasted 10 years and will likely last another 10.