To answer some of your questions:
Who was the original architect? -
Unknown. The course was built prior to clubs/courses commonly having a designated pro. Best guess is that it was built by the original members or by an early pro visiting the area or brought down to lay out the course.Assuming the originals are still in their same locations, which of the six-holes of today’s current routing were originals? -
If the course did originally have 6 holes (it had 9 by at least 1898 and the 6 hole reports appear to come from non-contemporaneous sources), I haven't seen any records that would allow us to track where they were.What year did the six-hole course become an 18-hole course? If it was 1901 (rather than 1912), was Ross the architect? -
As noted above, if the course did have six holes at one point, it became a 9 hole course by at least 1898. The 9 hole course was extended to 18 holes around 1905. The Ross work is described as an R9/A9 in 1915 from some sources, but as we know the course already had 18 holes prior to then.When did Flynn make any changes and what were they? Same questions for Jones. -
Flynn's work is credited as being in 1925, a few years after Peter Lees is credited with putting the existing 18 hole course in shape. No idea on Jones, but I'm sure someone around here could track that down.Here's a quick history of the first course at The Homestead.
Sources note 1892 as the start date, but the first mention I can find of a course comes from the 1896-97 Golfing Annual.
Jan. 1898 Golf Magazine notes a 9 hole 1,729 yard course that was to be extended by 600 yards.
The 1899 Golf Guide has a 9 hole 2,144 yard course.
Feb. 1899 Golf Magazine notes 9 hole 2,184 yard course recently improved.
Here's the 1900 Harpers listing:
The 1901 Harpers listing is the same as above but has a date of organization of 1896.
The 1902 Official Golf Guide listing:
Oct. 1904 Golf Magazine notes a 9 hole course with plans for an additional 9 with 15 total holes currently in play and the full 18 to be ready next spring.
Sept. 1905 Golf Magazine notes club has been in existence for around 10 years and originally had a 9 hole course which has was extended to 14 and now has 18 holes of 5,219 yards.
May 1913 Golf Magazine notes first 6 holes put in place 20 years ago now being over 6,000 yards.
The 1916 Annual Guide notes an 18 hole course of 6,017 yards with a date of organization of 1892.
Subsequent guides have yardages varying in the low 6,000's and the date of organization changes to 1899.Dec. 12, 1917 New York Tribune notes an 18 hole 6,264 yard course.
Dec. 1919 Golfers Magazine notes the Homestead had a 9 hole course and an 18 hole 6,242 yard course.
Nov. 1921 Golf Illustrated notes existing 18 hole course put in shape by Peter Lees.
Feb. 1932 Golf Illustrated notes this as an 18 hole course.
Some random photos:
1900 Harpers -
Sept. 1905 Golf Magazine -
Oct. 1914 Golf Illustrated -