The IAU vote was narrow,
Really? Their notes from conference indicate that the resolution "was passed with a great majority.": https://www.iau.org/news/pressreleases/detail/iau0603/
1. Nomenclature: An "adjective-noun" should always be a subset of "noun". A "dwarf planet" should be no less seen as a type of planet than a "dwarf star" is seen as a type of star by the IAU.
No. A dry lake is not a type of lake, for example. "adjective-noun" can mean "something in the category described by adjective but resembling the nouns". You can't make Pluto a planet by playing a cheap word game.
2. Erroneous foundation: Current research agrees that most planets did not clear their own neighborhoods
Nothing from the IAU's resolution indicates a purpose to consider the historical conditions. Your objection is semantic pedantry and can easily be fixed by wording the requirement as "has a cleared neighborhood". Also, yes Mars and Neptune vary in Stern-Levison values by 300x. That doesn't make the value unhelpful. And it doesn't change the fact that there's a gap of 10 orders of magnitude between any of the planets and the high Stern-Levison value of any dwarf planet (Pluto).
3. Comparative inconsistency: Earth is far more like Ceres and Pluto than it is like Jupiter, yet these very dissimilar groups - gas giants and terrestrial planets - are lumped together as "planets" while dwarfs are excluded.
Since was grouping of astronomical objects done by atmospheric similarity? That would be the worst rule yet.
4. Poor choice of dividing line: While defining objects inherently requires drawing lines between groups, the chosen line has been poorly selected. Achieving a rough hydrostatic equilibrium is a very meaningful dividing line - it means differentiation, mineralization processes, alteration of primordial materials, and so forth. It's also often associated with internal heat and, increasingly as we're realizing, a common association with subsurface fluids.
You are describing differentiation for a different purpose than the IAU's planet definition and then jumping to the claim that it is better. Your answer begs the question of what the purpose is for distinguishing a planet.
5. Mutability: Under the IA definition, what an object is declared as can be altered without any of the properties of the object changing simply by its "neighborhood" changing in any of countless ways.
Yes, we live in an evolving and mutating universe. Each of these planets came into existence at one point, so any definition involves some mutability unless you believe in a static, eternal universe.
6. Situational inconsistency: (Related) An exact copy of Earth (what the vast majority of people would consider the prototype for what a planet should be), identical down to all of the life on its surface, would not be considered a planet if orbiting in the habitable zone of a significantly larger star (harder to clear zone), or a young star (insufficient time to clear), a star without a Jupiter equivalent (no assistance in clearing), or so forth.
The definition is aimed at defining planets within our own solar system and not intended to be applied to exoplanets. You abuse this same limitation in another point below.
7. Ambiguous definition: There is still no consensus on what defines having "cleared the neighborhood" - in particular, what the "neighborhood" is.
While it's true that Resolution 5a didn't specify which discriminant to use, that doesn't make it ambiguous. There are multiple discriminants, and a common theme of all of them is that the 8 planets have discriminant values much closer to each other than to other objects in our solar system. For example, both Margots and and Soter's discriminants show a larger gap between Mars and Ceres than the full range of values from Mars all the way to Jupiter. These 8 planets are clearly a class of objects separate from others which orbit our Sun. There are also classes within our planets (gas giants vs rocky), but that doesn't prevent the usage of the term "planet" to apply to the class which clearly consists of these 8 objects.
That's as much of your Gish Gallop of misinformation that I have time to tackle.