1. Is just a nomenclature problem. The key issue was whether Pluto belongs in the same category as Mercury through Neptune.
First off, the problem category was called "nomenclature". Secondly, you act like mercury has bloody anything at all in common with Jupiter and Saturn. It's far, far more like Pluto. It's not an "edge case" issue, it's a fundamental misgrouping issue.
2. If a planet changes its orbit, one of two things will happen:
It clears its new neighborhood
It gets cleared out by a new neighbor or falls into a resonance with it
As was mentioned, this is not correct. Mars-sized planets don't clear their own neighborhoods. Mars did not clear its neighborhood - Jupiter did. Your "two things" are simply not accurate. It's a false supposition that's the entire foundation of this definition.
More to the point, extrasolar planets show how ridiculous this definition is even more. There are extrasolar planets larger than Earth which orbit their star closer to each other at times than the Earth is to the moon. They don't "clear" each other at all. It's just a ridiculous, completely false premise.
3. and 4. In geological terms yes, but I think the IAU was correct in preferring to define planets through orbital characteristics over geological ones.
Why? Why should we define what something is based on where it is rather than what it is? The answer is basically given in the question itself. When you say, "X is a planet", you're making a statement about what it is. That's the meaning of the word is. If you want single words to talk about orbits, we already have terms for that - that's what "asteroid", "KBO", etc are.
And really, you completely avoided these points. Pluto and Earth are far more like each other than either are like Jupiter. So grouping Earth with Jupiter and not Pluto is a complete absurdity. Hydrostatic equilibrium is a meaningful distinction - it has all sorts of consequences for the body. The nobody-can-agree-upon "neighborhood" definition has little to no bearing on what you're going to find there.
5. The neighborhood of a planet cannot be simply changed without significant consequences. If through some freak incident a formerly solitary planet ends up suddenly having a neighbor of significantly higher mass, that planet will not remain a planet for very long. Its "mutability" is then not even restricted to definition games, it will quite be literally destroyed or thrown away into deep space.
These are anything but the only two options. They can change orbits, migrate inward, migrate outward, get locked into new resonances, etc. A planet can be moved into for example a more out-of-plane orbit by an intruder and still receive the same insolation, and thus be exactly the same on the surface, but no longer be a planet. It's an absurdity.
6. An Earth-copy that hasn't cleared its neighborhood yet won't be an Earth-copy due to frequent crust destroying meteorite impacts
That's not true. For one example among many, the Earth copy and the other bodies in its neighborhood could both be in orbital resonance with a larger body.
. Such a child solar system will probably not be described well by our current terminology but these systems are also very rare because that phase of life only lasts for a very short time.
Yet another unsupported statement.
7. There will clearly eventually be edge cases, but Pluto isn't. There is an object with 10000 times its mass within its perihel and apohel. Its orbital period is not independantly "chosen" but defined by Neptune
And if Earth were located where Pluto is now, its orbital period would also not either be indepdently "chosen" but defined by Neptune.
Should I even bother mentioning that one of the leading theories to explain Sedna's orbit is that there is a roughly Earth-sized body out there? WISE isn't capable of spotting such small objects.
8. - 10. Those are all things that we are just now starting to discover.
No, they're not. We've known about exoplanets and binaries long before the IAU definition.
They might eventually change up the definition of the word planet again
They refuse to revisit the issue.
such as when we do find the first binary pair of planets with similar mass in the same orbit.
We already have one, Pluto-Charon. They refuse to acknowledge it. And binaries don't just affect planets - there are even binary asteroids.
11+ are mostly political points where you can have an opinion either way.
Dismissing points as "political" is a nice way to not have to actually address their substance.
But scientifically the question is: Are Pluto, Ceres, Eris and the 100+ other yet to be discovered KBOs really similar enough to the big eight to be in the same category.
Given that they're far more similar to Earth than Earth is to Jupiter? YES. Unambigulously yes. If you want to take them out of the category, you also need to say that either the terrestrial planets aren't planets, or the gas giants and ice giants aren't planets. And the ice giants really shouldn't be grouped with the gas giants anyway. Or we can just stop all of this nonsense and accept the practical definition that hydrostatic equilibrium is a really meaningful bound, and then subdivide "planet" into planet categories from there - dwarf, terrestrial, gas giant, ice giant, and all of the strange new types we're discovering in other star systems.