All of that does happen. Local gun control laws differ dramatically. Localities differ about how they handle free speech — protest permits for example, much easier some places than others. Some places are OK with expressions of freedom in the public square, others not as much. We’ve generally argued that the fact that San Francisco doesn’t want prayer in the schools or Nativity scenes on the City Hall lawn shouldn’t preclude Mobile from doing so. The Fifth Amendment requires that there be a public use. Localities can differ on how they define public use, but so long as a duly elected group makes a reasonable case that they are seeking to put the property to public use (and just compensation is paid), then the Supreme Court approves it. Always has.
No, this is completely incorrect. Look up the Incorporation Doctrine.
No locality can violate the Constitutional Rights of citizens in a manner contrary to the findings of the Supreme Court and the FedGov. Laws can certainly be different, but they cannot violate the roadmap laid out by the Constitution and the Federal Courts, so if the Court says "You can't ban handguns", then no locality can ban handguns, period. It doesn't matter if they want to define the 2nd Amendment differently, or define "arms" differently and say it doesn't include handguns. They don't have that power.
Localities can differ on how they define public use...
Of course they can, because of Kelo there is now no limit on the Takings Clause, and localities and municipalities working in tandem with whatever private entities are lining their pockets can now define anything as a "public use". Anything.
If Kelo had been decided correctly however, and a public use was defined as actually being a public use, and not a public benefit or some other generality, then Pfizer and Donald Trump would not be able to take someone's house and build a pharmaceutical plant or a limo parking lot.
In other words, if Vera Coking's case had been decided post-Kelo, she would have lost.
As I lined out earlier, the only good thing to come from Kelo is that real conservatives in the state governments rushed post-Kelo to establish state prohibitions on eminent domain and state and local limits on the Takings Clause, because the decision was so heinous.