The San Francisco Symphony has an unabashedly populist side that is refreshing and possibly also remunerative — not a small consideration for an expensive institution. Celebrating the opening of the Walt Disney Family Museum with music from classic Disney films will make a pops concert of great variety, however. Lisa Vroman, a terrific soprano who spent years in San Francisco playing Christine, the female lead in Lloyd Webber's The Phantom of the Opera, will sing some of the great songs from Disney films, and the orchestra will add some selections from Fantasia, including Mussorgsky's Night On Bald Mountain, and Beethoven's Symphony No. 6 (“Pastoral”). Unlike some of his peers at other studios, Walt Disney actually knew a good tune when he heard one.