Q. Do you know where Wayman Crow's business papers and correspondence are?

In addition to the Crow Genealogy Collection at Washington University Archives, you may also be interested in the following:

The Missouri History Museum (Library & Archive Division) has a collection of “Crow Family” papers.

There are also some of his correspondence in the Papers of Harriet Goodhue Hosmer, 1834-1959, and Additional papers of Harriet Goodhue Hosmer, 1848-1915, located at the Radcliffe Institute, Harvard University.