Chicken a la King - the continuing story

Slow Foodie-friend Paul knows a lot more about recipes than I do, and is a great researcher. He wrote me this:
Chicken a la king
In the seventeenth century, English chefs borrowed the French phase a la roi roi and applied it to certain fancydishes such as mutton a la roi. The culinary phrase a la king, which did not become common until the twentieth century, might appear to be a direct translation of a la roi, but in fact is has another origin: it likely comes from Clark King, a New York hotelier, who around 1915 had the distinctions of having the dish known as chicken a la king named after him.
Source: Mark Morton Cupboard Love: A Dictionary of Culinary Curiosities, 2004.

But there are more explanations of the origins of Chicken a la King:
There are many stories about the origin of Chicken a la King, and many of them sound plausible. It is a dish of diced chicken, mushrooms, green peppers, and pimientos in a cream sherry sauce served on toast. Here are some of the stories. Dates range from 1881 to the 1920s.
1) Either a Mr. or Mrs. Foxhall Keene suggested chicken a la king to the chef at Delmonicos Restaurant in New York City, and originally served as Chicken a la Keene. This was in the late 1890s.
2) The chef at Claridges Hotel in London created it in 1881 for sportsman J. R. Keene (Foxhalls father from the story above). J.R.s horse, possibly also named Foxhall, had just won the Grand Prix in Paris.
3) A variation on 2), that the chef at Claridges named the dish after his father, J.R. King.
4) Chicken a la King was created at the Waldorf Astoria in New York City in the early 20th century.
5) An American invention created in the 1920s on Long Island, New York, or in Miami, Florida.
6) The most likely candidate. Created by Chef George Greenwald, at the Brighton Beach Hotel, New York in either 1898 or the early 1900s. He prepared a special chicken dish one evening for the owners, Mr. and Mrs. E. Clark King II. The next day, either Mr. King loved it and wanted it on the menu or Chef Greenwald asked if he could put it on the menu. In either case, it was added to the menu as Chicken a la King (1.25 dollars), and quickly became a great success.
Source: http://www.foodreference.com/html/artchickenalaking.html

I go for this last explanation. The New York elite used to spend their summers at this Cony Island Hotel at the turn of the century. (19-20). Anyway: it is a very American recipe in my opinion, and a modernisation of chickenmushroomfricassee, a bit fusion in fact, with the green peppers and piementos.
Thank you Paul!