Tom,
Your list is shrinking.
Belmont Springs was not open in 1908...not in 1909 either...and in 1910 had a nine-hole course designed by the land owner Willard Robinson, not Donald Ross. Do I have to cross check all of your work??
Therefore, The number of courses a club considering a new course could look to in 1910 that were;
1) Solely designed by a golf professional
2) Already open for play and therefore viewable as to achieved results
3) Not already been significantly revised by an amateur such as Walter Travis
and
4) Not significantly revised based on recommendations of a professional in 1910 with changes likely not yet in the ground, we're left with...
the following courses as examples of the excellent work and pinnacles of over a decade of achievement by professional golfer up until 1910.
Beverly - G.O'Neil (1908)
Minikahda - W.Watson/D.Foulis (1899), J.Jaffray/R.Taylor (1906)
Atlantic City - J.Reid (1897), H.Barker (1909)
Baltusrol - L.Keller (1895), T.Gourlay (1896), G.Low (1908-10)??
Englewood - J.Hobens (1905)
Apawamis - T.Bendelow (1899), H.Strong (1906-10)?
Fox Hills - P.King/D.Brown (1901)
Waverly - H.Barker (1910)