With great joy I can report answering my own query, after many years! Tonight, while looking through the new image files available for Chittenden District (Vt.) Probate on www.familysearch.org, I came upon a probate-court order of 30 April 1824 that decreed $28.85 1/2 each go to Chloe Bell; Robert Cook (identified on another sheet in this file as a son of the decedent); Laura Cook; the (unnamed) wife of William Wells; the (unnamed) wife of Pharez Phelps (known to be Elizabeth Cook); and the (unnamed) wife of B.F. Everest (known to be Eunice)--as heirs of Benjamin Cook late of Milton dec'd. Benjamin F. Everest (1787-1830) of Milton (second son of Lieut. Benjamin and Martha "Patty" [Fuller] Everest of Addison, Vt.) was his father-in-law's administrator. On 28 April 1824 Benjamin Cook's widow "Patty" [Martha] signed (with her mark) a receipt for the articles set off to her; Eunice Everest witnessed.
In 1850, at Milton, Eunice (Cook) Everest gave her age as 57, her birthplace as Mass.; her age at death in 1852 is given on her gravestone at Milton Village Cemetery as 61. Eunice's brother Robert Cook (c1786-1868, bur. West Milton Cem., as "Robert G." Cook), was also at Milton in 1850, and gave his birthplace as Mass. (the enumerator's scrawled abbreviation has been mistranscribed by Ancestry as "Mississippi." There is no equivalent birth (in Mass., as son/dau. of Benjamin) at familysearch or on rootsweb for Eunice or Robert, that I can find; haven't yet found any of the others.