In English usage in the 17th, 18th and 19th centuries Mr. and Mrs. were used for a much wider range of people than Herr and Fru in Sweden. In England anyone, save labourers, workers and servants (and the titled nobility of course), would be called Mr. and Mrs.; a farmer, a shop-keeper but also the grand-children of a duke. However, there would be a difference if you wrote to them: a gentleman (what we'd call ståndsperson) would be addressed as Mr. John Doe, Esq. or if it was a grandson of, e.g., a baron it would be The Hon. Mr. John Doe while the shop-keeper would be plain Mr. Dash.
Before about the last quarter of the 18th century, Mrs. wasn't contracted but would instead be pronounced as it was spelled, Mistress. At this time, there was no Miss; an unmarried girl would be Mistress Jane while her mother was Mistress Doe. In Scotland this usage was continued well into the 19th, and I think some places into the 20th, century.
As for servants female heads of department (the house-keeper, the cook) would rate a Mrs. (and surname) by both their employers, colleagues and subordinates, while male heads of departments (the butler, the cook, the gardener, the head groom, the head coachman) would be called by their surname by their employers but Mr. (and surname) by their colleagues and subordinates. Personal servants - a lady's personal maid (dresser), a gentleman's valet, the children's nanny - would be called by their surname by their employers but Miss (the dresser), Mr. (the valet) or Mrs. (the nanny)(and surname) by their colleagues and subordinates (their colleagues included all heads of department).
Genteel employees - i.e. employees with a social background similar to the employer's - like governess, companion, chaplain, personal secretary, tutor would always be called Mr., Mrs. or Miss, as the case actually was (while a house-keeper very seldom had married a companion might well have).
Subordinate servants, like housemaids, footmen, gardeners, grooms etc. would be called by their first name.
Soldiers (privates) would be called by just their surname.
Ingela
PS. Cornet - modern Swedish spelling kornett - was the lowest officer rank in the cavalry, until 1835 when it was changed to fänrik. The exact English translation for the exact same rank is cornet (in England the title was abolished in 1871, replaced by second lieutenant).