From Wikimedia.
I do not know if the fully-dressed girl in the foreground is Marie Thérèse, born in late 1778 so not quite three. Marie Antoinette is in bed. The Lady holding the Dauphin may be the Duchesse de Polignac or Victoire Armande Josèphe de Rohan. The Lady serving a drink the Queen wears a robe à la française while the girl wears a round gown, maybe a robe à la circassienne with train. The Ladies appear to be wearing much reduced forward-back flared engageantes.
Keywords: 1781, Marie-Antoinette, Archduchess, Queen, Habsburg family, Bourbon family, French, long bouffant straight coiffure, feathered cap, feathered jeweled headdress, square décolletage, modesty piece, elbow length tight sleeves, forward-back flared engageantes, panniers, apron, flounces, lace, over-skirt, robe à la française, robe à la circassienne, necklace