Professor Park's anecdotes (at 28:50) about Ernest Hemingway and Robert Louis Stevenson and their lost/destroyed manuscripts are well documented and the stuff of legend, however there is no evidence that Herman Melville lost an early version of "Moby Dick" at sea.
When Jason and Mamie play "Listen to the Mocking Bird" Mamie is clearly faking it on the tin whistle.
At 4:15, Jason's dialogue is quite echoey until he approaches Grandpa when the audio suddenly becomes normal. This was likely an error where the boom mic operator was supposed to have the mic positioned over Jason and track with him as he walked across the kitchen. Instead, the mic was positioned over Grandpa, which explains why Jason's audio improves as he walks towards him.
Elizabeth refers to her doll as a "she" although it is clearly a Raggedy Andy doll and not Raggedy Ann (which she or one of her sisters have owned previously).
When John calls up to John Boy on the second floor of the house, the light that is supposed to be John Boy moving around inside with a flashlight is clearly a spotlight shone from the outside of the house.
The episode takes place in 1935, yet the book Elizabeth is reading after she returns home is "My Second Book to Read," which wasn't published until 1957.
It's doubtful that Grandpa's space heater caused the house fire. Electricity would not have been available in rural Virginia until after 1937, IF the family could afford it.