You don't seem to have moved on much -
If DD is aiming to become professional, I am sure you are all aware it is a VERY TOUGH world out there! If she is performing for fun, then just enjoy it, and get involved in as many performance opportunities as she can.
I played semi-pro drums for around forty years, but never became good enough to get professional. But I did pubs, clubs, student big bands, folk, country-rock, pantomime and musical theatre, barn dance etc. And as a Teaching Assistant I coached primary children to accompany in school performances, and ran recorder, keyboard and percussion clubs.
These days, with amplification and recording, a huge voice is not necessary. Peggy Lee, Blossom Dearie, and today Lily Allen, are not powerful singers, and there must be others who are, nevertheless, effective performers. And even a LOVELY voice is not always essential - think of Eartha Kitt or Louis Armstrong.
Playing for Old Time Music Hall, in the '70s, our pianist had several talented children, who today are prominent in the stage musical world; I knew Maria and Sonia Friedman, when they were 14 and 8 respectively.
Listen to Maria Friedman's recording of "Broadway Baby" to hear what REAL singing is!