I'm pretty sure the last three photos are of a coontie (or comptie) mill. Here's an excerpt from Tequesta: The Journal of the Historical Association of South Florida that I think describes the mill depicted in this album.

Manufacturing starch from the coontie root is probably the earliest known industry in Dade County. The Indians are credited with the discovery that starch could be extracted from these roots which once grew so abundantly on South Florida's high pine land. However, it has been established that white settlers engaged in this industry some time prior to 1840.

The coontie root, a species of Zamia, was also known as Florida Arrowroot. The early settlers called the root and the starch obtained from it "comptie." It is believed this name was derived from the Indian pronunciation. Northern biscuit makers, principal users of the product, called it Florida Arrowroot Starch.

The roots of this cycadaceous plant are found one or two inches below the surface of the ground and resemble a large sweet potato in appearance. Each plant puts out several red stems bearing small fern-like leaves. There is a male and a female plant, the latter being distinguished by a cone-shaped seed pod which grows just above the ground. The coontie root itself is quite poisonous. Therefore, it was necessary to crush the root and wash the starch entirely free from the poisonous pulp. Historians have reported instances where men, who were lost and starving, ate the roots in the mistaken idea they were edible. The results were usually fatal.

Birds are the chief planters of coontie roots, plucking the seeds, eating the meat therefrom, and then dropping the seeds while in flight. Because of their slow growth, it was not practical to cultivate these plants commercially. This, coupled with the gradual disappearance of the forests, was an important factor in bringing about the industry's eventual demise.

The process employed by the Indians was crude and it remained for the early white settlers to improve on these primitive methods. Long before Miami came into existence, nearly every family living in this area had its own little starch mill. Whenever any extra money was needed, the whole family would get together and make starch. Some mills were operated entirely by hand, while others employed mule and horse power. In later years, there were a few motor driven mills, including at least one large steam driven mill located in the vicinity of Little River. This mill was owned by A. B. Hurst, and remained in operation until 1919, when it was moved to the southern part of the county near Kendall. It continued in operation at this new location until 1925.

In order to describe the type of starch mill being used in South Florida just prior to and shortly after the turn of the Century, the writer personally interviewed Mr. John B. Hurst, son of the aforementioned A. B. Hurst, and Mr. Willie Mettair of North Miami, Florida. The latter was actively engaged in the manufacture of starch before 1900.