With the Appendix A quote in mind ('Last Ship' and etc.; noting also the 'some say' part and the implied author(s) with
'...before we came to the Shire' in this passage), in
Of The Rings Of Power And The Third Age Círdan is said to have spoken to Gandalf, his words ending with:
'... and I will dwell by the grey shores, guarding the Havens until the last ship sails. Then I shall await thee.' And...
'White was that ship and long was it a-building, and long it awaited the end of which Círdan had spoken. But when all these things were done, and the Heir of Isildur had taken up the lordship of Men, and the dominion of the West had passed to him, then it was made plain that the power of the Three Rings also was ended, and to the Firstborn the world grew old and grey (...)'
In my opinion the implication here (at least) is that the 'last ship' refers to the ship prepared for Gandalf and Elrond and others. Not that is solves anything of course, but another piece for consideration maybe, including that Círdan had held one of the Three.