Cheers!

- It is very rarely ever referred to as “Kölschbier” by the locals. Kölsch is the word to use, and it is assumed your interlocutor will understand from the context that you mean the beer, not the local dialect.

- The style guidelines are defined in the 1986 “Kölsch-Konvention”, which states, apart that the beer has to be produced within the greater Cologne boundaries, the beer must be pale, top-fermented, hop-accented, filtered and between 11 and 14% dry extract.
This means that unflitered Kölsch such as Brauhaus Heller’s has to be called “Wiess”. (”white” in local dialect, not a typo̷

- The Clinton story (1999, during a G8 meeting in Cologne) is as far as I could gather from the locals, mostly apocryphal.
What is established is that Clinton had to go have a drink at Malzmühle which was his second choice. First choice was Lommis, a now-defunct Päffgen Outlet on Köln-Deutz, rundown and shabby, but 200% authentic.
When approached by Clinton’s entourage, the owner, Mr. Lommerzheim, told them flatly that Mr Clinton could indeed come have a drink, but that he would not close his bar, because his regulars would then have no place to go.
This story says a lot about the spirit of Cologne’s beer places : no matter who you are outside the door, once inside, you’re all equal.

Indeed, Kölsch has to be experienced once in your life in one of Cologne’s better beer establishments.
As you mentioned, it is then dispensed by gravity, without extraneous gas, which showcases its natural, gentle, fine condition. Since gravity-served Kölsch usually is unpasteurised, this makes for a quanching, crisp, delicate, but surprisingly complex beer.

Cheers !