Yes, folks who want to see Song of the South can find copies of it by looking around a bit on the net. I ran across a dozen VHS copies of it (extracted from that Japanese laserdisc) at a swap meet about ten years ago, and there are several DVDs available from places in Thailand and the...
"Waitin' for the Robert E. Lee" was performed in Babes on Broadway, not Strike Up the Band. There is a minstrel show in Babes in Arms, too, though it's not as famous as the one in Babes on Broadway.