Princess Alice, Countess of Athlone born Princess Alice of Albany. Her father was Queen Victoria's 4th son Prince Leopold, Duke of Albany 1853-1884. At the time Princess Alice is talking about the family would have been her mother Princess Helen, Duchess of Albany and her brother Prince Charles Edward, Duke of Albany later Duke of Coburg.
This is just a guess, but I think the only tree that wasn't real was the rotating one. The one on the left does appear in both pictures, so I'm guessing that is the rotating one.