Use the ampersand when it is part of a company’s formal name: Baltimore & Ohio Railroad, Newport News Shipbuilding & Dry Dock Co.
The ampersand should not otherwise be used in place of and.
Identify a person by first and last name on first reference. On second reference, use last name only. Using first names on second and subsequent reference is OK, however, if it’s someone you know and you have made that clear to the reader in some way.
On first reference, you should also attempt to identify the person’s provenance, i.e., “popcorn mogul Orville Reddenbacher once said …” or “food blogger Jane Doe writes … “