Regarding the use of ' staff', as in the company staff.
How do we use the plural?
1. The company has five staves.
2. The company has five staves.
"Staves" is generally only used as the plural of "staff" when referring to the staff used in musical notation, or a staff used as a mast or weapon.
When referring to personnel, "staff" is the proper word. "The company has five people on staff." or "The company's staff is divided into three departments: Executive, Clerical and Sales."