Elizabeth picks up a book which Darcy identifies as Sun Tzu's L'Art de la guerre. The book is 2 inches thick. The Art of War is only a short pamphlet which takes less than 1 hour to read.
Except for the first zombie-killing scene where Darcy wipes blood off his dagger, there is no blood on any of the weapons or their clothing after they slay the zombies.
When the sisters are dressing for the dance at the beginning of the film, they are shown sheathing several styles of daggers which were not manufactured until the 20th century. This includes an Applegate-Fairbairn fighting knife which was designed by Rex Applegate and William Fairbairn in 1941.
The Bennett sisters' shaved armpits and legs are only possible with modern razors.