Google told me before I finished inputting my search term yesterday: Myrtle K. Hilo. Autofill wanted to add the word obituary. She passed away on October 3rd.
Other falsetto singers had nicknames befitting the prettiness of their tone. Linda Dela Cruz was "Hawaii's Canary". Lena Machado, was "Hawai`i's Songbird". Myrtle K. Hilo, however, was known as "The Singing Cab Driver". Although gifted with a vocal range that was similar to that of her feathered sisters, Myrtle's husky tone set her apart. For lack of a better word, she sounded authentic. On her first two records, that raspy tone and bold falsetto was complemented by loose arrangements that featured a steel guitarist whose reverb-laden tone had clearly made a detour in Tahiti and a loud and lounge-y pianist. Find those records if you can, close your eyes and imagine yourself at a nightclub in late 1960's Honolulu.
When she wasn't working the nightclubs or working as a DJ, or appearing on Hawaii Five-0 (and sometimes even when she was), she drove her cab. What a treat it must have been to listen to the kanikapila at Charley's Taxi Stand in those days.
A 2002 article about Myrtle K. Hilo is here.
Her obituary is here.
Listen to her music at mele.com.
See her in these three episodes of Hawaii Five-0:
Season 2: Run, Johnny, Run (Napua Mala. This episode also features a young Christopher Walken)
Season 4: Air Cargo: Dial for Murder (Kim Wong)
Season 6: Secret Witness (Old Woman -- funny that she played that role 35 years before she died!)