I picked up a book called "Who's Who in Yachting" (1966, Yachting Club of America). There are a number of Herreshoff Boats - some additional info for the registry....
1. Some fill in info - Schooner Haswell (#743) - was known as Diablo and owned at the time by - Frank S. Wade of long beach CA - She's listed as "not found" in the registry so maybe this is a place to start research.
2. There is an S class named Gander II: - owned by Dr. Judd Bockner of Mamaroneck NY due to her build date listed I believe she could only be # 1151 Pluckermin II or #1129 Suprise. The answer may lie in her Sail #, which in the book is listed as S-50
3. The FI 23 Contest (#1505) is listed as "not found", but in the book she is named Glading III With a sail # H-23-2 ; owned by Dr, Alan G Harquail jr. Annapolis, MD - Again maybe a place to start research.
4. Ibis NY30 - is listed as owned by a William A Wolf of City Island, NY
5. Kestrel (FI 31) is listed as owned by a Tarbell - in the registry you have 1980, so either this is his father (1966) or he owned her earlier.
6. There is a Northeast Harbor 30 Listed as named Lola - its impossible to tell which one as they are all built at the same time but she had sail #4 if that helps. She was owned by a Thomas Wadlow, Mystic, CT.