Incidentally, the Epilogue to LotR, which was omitted from the published versions for obvious reasons [and is now to be found in History Middle-earth IX], but not because the ideas therein are abandoned, gives some information.
King Elessar still called the city Minas Tirith, as becomes obvious in the title of the letter he sends Samwise: "To Samwise and Rose the King's greeting from Minas Tirith" (HoME IX, xi).
It also becomes apparent from that that the King still perceived MT as the capital of his realm. Note that at the time of said letter he had not been in the North since Elanor was very little, i.e. more than 10 years.
However, I'm afraid I cannot say anything definte about Minas Morgul. The Nazgûl were utterly destroyed, and Elessar was expanding his realm far and wide, so it would at least seem surprising if he shouldn't have also taken Minas Morgul back. Resettling or renaming thereof might be another matter entirely.
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