I don't know that I would have recommended reading Port of Shadows in anything like the order it supposedly falls in the timeline. Particularly with 30+ years between the writing of each. Clearly, as you've pointed out, the author can and usually does change a lot over that much time, so even though to me it felt fairly similar in tone, I'm sure that it is pretty glaring when going from the first 3 to that one.I finished Books 1-3 and was about to pick up 4 when I saw that this Novella called the Port of Shadows was set in between 2-3. I am now about 75% done with Port of Shadows and my first impression was to check the Author's name because I feel like it is a different writer. I feel like Croaker is a bit different person when compared to 1-3, it's just little things like phrases, humor and self reflection...they all seem a bit off. I have every intention of finishing this book, however a few times I have thought what is the point and then I remember...
That I am getting an origin story of the Lady. The best parts of this book are the Necromancer chapters. The whole Tides Elba/Mischievous Rain twins with Craoker is just nonsense, there is no way that he would have twins with a Taken and never mention it in Book 3, The whole scenario seems hamfisted.
Now with saying all that maybe I am in for a big surprise where everything will come together, make sense and be wrapped with a pretty bow. I am very hopeful that will be the case, but in the meantime it is frustrating to read the narrator (Croaker), a guy I feel like I know and yet he feels so foreign and has kids etc. Right now the best i can give this book is a 3/5 and that is being very generous and overly forgiving because of the Necro/Senjack stuff. I really really hope I come back here in a few days and say something like "oh I get it now"
That being said, as I mentioned before, given that (for obvious reasons) this book is never referenced in any of the later books, the reason for them never mentioning it is about as good as I can think of. Plenty of other books don't even try to address why we never knew all this shit before, but at least this one tries.
Also, amusing that a 400 page book is a novella nowadays.