I’m really hoping that Fallen London does something more with this NPC. I wish I wrote for them, I have so many ideas relating to her. I’ve heard that she has a bit of content in SSeas, but as someone who can’t afford toothpaste I unfortunately cannot get it. Is there a reason she’s the only supposed ‘Clay Woman?’ Is she like the unfortunate Comtessa? Speaking of, would the Comtessa become sentient clay or would she stay a statue? There should be a game solely relating to Polythreme and Clay Men. Too many questions, not enough answers, not enough content to overanalyze. FBG, I’m begging you. Give me Pirate-Poet backstory, please!
The Pirate-Poet is the focus of a substantial and very very good storyline in Sunless Sea. The game is often on sale on the Humble store, GOG, and/or Steam. I recommend trying to pick up SSea at a discount and playing it for yourself if you want to know more about her.
As for the Comtessa, that’s not really known because we don’t ever see her again. Perhaps the exceptional story The Clay Man’s Arm has some clues, but I’ve not played it myself nor heard much about it either positively or negatively.
Much can be learned about Polythreme and the Clay Men in the Clay Quarters of London and at Polythreme itself. The mid-late stages of the Heart’s Desire ambition and the Educating Lyme branch of Pygmalion at Mahogany Hall may also be worth a look if you want to learn about the Clay Men.
Iirc the Pirate-Poet was originally a normal Clay Man and simply decided that she was a woman. No clue whether she was Unfinished though.
Common zailors refer to the Poet as Unfinished, but the Modiste - who knows her personally - says she isn’t, and notes how unusual it is for a regular Clay to rebel against the Hundreds, and, by extension, her own apparent nature.