The first appearance of MARIE was as a serialized novel, published in Cassell's Magazine from September 1911 through February 1912. A.C. Michael created 20 illustrations and 1 headpiece for the serialization.
McKay, Scott, and Whatmore claim that Cassell and Company published the first edition in book-form in London on January 25, 1912. Only 4 of Michael's 20 illustrations are in this edition, though one of them is in full color. There are no ads at the end of the book. McKay and Scott claim that 6,997 copies were printed and bound in the same style as the American edition. Scott claims another 3,936 copies were bound in cloth and 2,571 copies were bound in paper wrappers for the Colonies, except Canada. Canada got its own binding, consisting of 2,000 copies.
Higgins claims that Cassell and Company paid £450 ($76,000 in 2020 dollars) for the serial rights, and £750 ($126,000 in 2020 dollars) was advanced for publication in book-form.
Longmans, Green and Company published the first American edition March 18, 1912. McKay and Scott both agree on the publication date in New York. The American edition used the same illustrations as Cassell did for its edition. There are no ads at the end of the book.
See the VisualHaggard.org page dedicated to the illustrations found in various editions.
Notice that the British first edition was first published January 25, 1912, and this copy was signed 5 days later.
According to Sumner and Stillman, booksellers out of Maine: "Mrs Sarah Pitt was a writer of novels meant for children, or at least young adults -- for whom Cassell was likewise the UK publisher; she had been quite popular during the years 1881-1900."
I am not certain that they are correct, but their theory sounds reasonable.
I also own a copy of the 1st printing, and a copy of the 2nd printing
Four of the illustrations are signed "Francis" and the other 3 are very similar to 3 of the original A.C. Michael illustrations found in the Cassell's Magazine serialization.