I am intrigued by your conspiracy theory and would like to subscribe to your newsletter. Why did they want to "specifically exclude Pluto"?
Pluto is notoriously different from the other eight planets, as can be explained in very elementary terms [1]. So, not to open any wounds, but the question is inevitably raised as to whether it is the same kind of "thing" as the other planetary bodies.
The actual planet itself is very active geologically and has a whole system of moons. The only reason you'd say it's very unlike the other 8 is due to orbital dynamics, i.e. due to other bodies besides itself. This is a strongly anti-planetary-science bias, IMHO.
Sooo... mass and composition are irrelevant? Because Pluto (and its fellows, like Eris) are smaller than a half-dozen moons. Pluto has less than _five percent_ of the mass of the smallest planet, Mercury. It is also mostly _ice_ unlike the inner (rocky) planets and the gas giants.
And variety of solar-system bodies are geologically active, from the inner planets, through numerous moons, down to comets and asteroids, and probably many other Trans-Neptunian Objects like Pluto (many of which also have moons). Your proposed criteria fail to be useful.
Pluto is notoriously different from the other eight planets, as can be explained in very elementary terms [1]. So, not to open any wounds, but the question is inevitably raised as to whether it is the same kind of "thing" as the other planetary bodies.
[1]. https://airandspace.si.edu/stories/editorial/pluto%E2%80%99s...