Is The Philosophical Zombie Argument Sound and Valid?

Here I'll discuss whether the infamous zombie argument currently confirms that its conlcusion is true.  The logic of the argument is generally accepted (so long as no semantic equivocation is happening), so that leaves us with whether the premises are true in the required sense.
Good writing on the subject has been done by both Richard Carrier (for example, in Sense and Goodness Without God) and Allin Cottrell (see here).
==Are they in fact logically coherent?==
Is there in fact no logical contradiction in saying something is both (1) physically indistinguishable from a living person, and (2) without any of the subjective experience?  How can we tell for sure?
If all you can say is that they are maybe logically coherent, then all you can say is that maybe physicalism is false.  Which I already admit: maybe physicalism is false (thus the zombie argument would not get us anywhere new), but very unlikely.
So how can logical contradiciton either be found, or ruled out?  We have to know all of the details and implications of the two things, and see clearly either a presence or absence of logical contradiction.  There is no other way to be sure.  All other ways are just educated guesses, that can be mistaken.
So what are all the details and implications of the two things?  I submit that we don't know all the details, nor all the implications.  Does anyone have an atomically precise map of a working brain (not a dead one)?  Does anyone have such precise knowledge to accurately predict what it will do even a few seconds from now?  No.  Yet that information might be relevant, no?  How can you be sure it wouldn't be?
Consider what is happening when we refer to subjective expereince.  As I say, we don't have the details, but we know that when we write or speak about such things, there is at least a lot of physical cause and effect going on.  If we knew the details and explored that chain of cause and effect, and really understood why each physical part was causing the other phyisical part, would we not see that this thing being referred to called "subjective expereince" was also physical?  How can you be sure from the armchair, before these details are known to look at?  How can you be sure you wouldn't look at that info and go "oh I get it now!  Amazing, that's how our subjective experience is truly physical!"?  You have to be sure this couldn't happen, and you need good convincing reasons to be sure, otherwise you can't say for sure that a p-zombie is even coherent.
One reason people seem so sure of this comes down to what the "inverted spectrum argument" claims.  So that would be another question I'd have to look at.  It's much more convincing seeming, too, because it asks us to explain the very precise thing that we don't presently have a fully confirmed explanation for.  But it still fails in the way all a-priori discoveries fail.  We could look empirically and find its conclusion to be wrong.
I'd go so far as to allow that the behavior might change if you remove the non-physical.  That maybe a physical body would become lifeless if it required a non-physical mind, and that non-physical mind was deleted or whatever.  Then, physical laws would be violated or whatever happewns when ghosts posess physical objects.
Is something non-physical required for subjective experience?  I admit I don't see any way that such a priori reasoning could give us any conclusion other than "maybe, maybe not".
(All hypotheses, no matter how silly or unlikely, will have to be assigned a non-zero probability of being true.  A tiny tiny fraction of a percent is still not zero percent.  So that's still a "maybe".  Kind of like maybe reptilian shapeshifters from another planet secretly control our government.  But not likely.)
==Would the logical coherence of p-zombies surely refute physicalism?==
Is this the kind of thing where we can say that if an alternative is logically possible, that the alternative is necessarily true?