If they were marooned on the island in 1897...
Im probably not the first to notice this but in the beginning it says: "The South Pacific 1897". Im Asumming they were 2 years old when they were marooned on the island and according to wikipedia they were eight years old when their mother died. then when the others come Lilli explains that their mother died 6 years ago, which would make them 14, thus the year would be 1909.
so why does the ship still have a mast? im no naval expert but im pretty sure in 1909 steamships were common place. and also the sailor has a Winchester Repeating Rifle, i think it would be more "historically" accurate if he had a bolt action rifle, like the Lee-Enfield.