New 'Scooby-Doo' Daphne Mckenna Grace Analyzing Sarah Michelle Gellar's Performance

Mckenna Grace might be a new, meddling kid in the "Scooby-Doo" legacy ... but, she's still got a love for the classic Daphnes -- including Sarah Michelle Gellar! We caught up with the star at the airport early Wednesday morning ... and, jinkies,…