Mary Jo --
The National Park Service lists names of over 2,200 officers and men for the 7th Mississippi, and you can browse their list for individual soldiers assigned to Company "F". I'm sure many of these are duplicates, but the names are there. Jamie has been through all the National Archives records for the regiment to cull out the duplicates and present the names correctly.
Were you not able to access either list?
A roster is a list of officers and men belonging to a company on a particular date. Were you interested in the original company roster submitted when it organized in 1861, the roster as it existed during William Green's brief term in service, or a list of all officers and men who ever belonged to this company?