This is a fascinating old thread, not only hitting on some interesting conversation points, but also highlighting some of the personalities that no longer post here.
From a historical standpoint, the initial question asked may be one that we will never answer. All of the architects noted in the thread (Flynn, Langford, Stong, etc.) were doing work in Florida at the time, but so were a bunch of others including Stiles and Van Kleek, who were probably the most prolific designers in the state in the 1920's.
But the name that stands out as the strongest possibility for one of the two architects who lost out to Ross is Charles Banks.
Of all of the guys noted, it was probably Banks who had the greatest connections to E. F. Hutton and the other founders of Seminole, all as a result of Seth Raynor's connections with Paris Singer.
It was Singer who hired Raynor to design The Everglades Club and the Palm Beach Winter Club, and Singer had engaged Raynor to design two additional courses in the area north of Palm Beach. The first, the Cragin Park course, was to be located directly across from Singer Island and associated with Singer's Blue Heron Hotel project. The second was a course to be built in conjunction with the Winter Club north of Kelsey City (which today is known as Lake Park). When Raynor passed away in early 1926, plans for these two courses were in the works, and every member of The Everglades Club would have been aware of them (including Hutton and whatever other founding Seminole members were associated with T.E.C.). Enter Charles Banks, who at that time took over Raynor's practice.
Newspaper reports from just after Raynor's death note Banks was to continue the work started for Singer in the Palm Beach area. Unfortunately, Singer's interests were taking a downturn, in part at least due to the massive hurricanes that ravaged the Palm Beach area around that time, and all of his projects seemingly ground to a halt. Just about the only major activity that took place on a Singer property in the later 1920's was the expansion of The Everglades Club.
There isn't much known about the second course to be built north of Kelsey City, other than it was located north of the inlet of the Florida Intercostal Waterway that bordered the location of the Winter Club (today's North Palm Beach CC). This area is remarkably close to where Seminole GC was built.
This course, as well as the Cragin Park project, died on the vine. But in a conversation replete with speculation, one can imagine the scenario where Hutton and the other Everglades Club members sought out the advice of the right hand man of Raynor in the initial plans for a course to be located in the proximity of areas in which Raynor had built and contemplated building courses and Banks had been on tap to complete those plans.
Sven