Who is Lionel Greenstreet, Hubert T. Hudson, Alfred Cheetham, Louis from Endurance: Shackleton's Incredible Voyage and what is their importance?

The indicated men are the remainder of the crew of the expedition. Greenstreet is the first officer; Hudson is the navigator; Cheethan is the third officer; Rickinson is the first engineer; Kerr is the second engineer; Wordie is the geologist; Hussey is the meteorologist; James is the physicist; Clark is the biologist; Marston is the official artist—a few of his images are included in the text; Green is the ever-optimistic and capable cook; How, Bakewell, McCarhy, McLeod, and Vincent are able seamen; and Holness and Stevenson are the fireman. All of the men are, to some extent, described in the book though not nearly to the same degree as the individuals separately enumerated.