The four sisters of Empress Elisabeth of Austria, popularly known as Sissi:
Helene Caroline Therese, Hereditary Princess of Thurn and Taxis.
Maria Sophie of Bavaria, Queen of the Two Sicilies.
Mathilde Ludovika, Countess of Trani
Sophie Charlotte Augustine, Duchess of Alencon
Picture n- 1 and n-3 are the same person, Mathilde in Bavaria, countess of Trani.
This is Helene aka Nene, Princess of Thurn and Taxis
Mourning evening dress, 1861
From the Metropolitan Museum of Art via Hyperallergenic