firstname.lastname@example.org has full edit capability on the spreadsheet, up to and including adding edit permissions to additional users (presumably woodsale committee members).
Someone from the woodsale committee should receive an email notification every time a new row is entered into the spreadsheet (i.e. a prospective customer fills out the form on our website and sends it to us). To accomplish, the email@example.com account should sign on, access the Firewood Sale Inquiry spreadsheet, and go to Tools > Notification Rules... Select Notify Me when User Submits the Form and select the preferred rate of notification (immediate or daily).
It is up to the woodsale committee to determine proper procedural response to an inquiry being received. But additional columns on the spreadsheet for "Date of Follow up", "Who Followed Up" and "Follow up Notes" give a direction on what that process might be.
Also note that in order for the woodsale inquiry to make it all the way to a real monitored mailbox, the holder of the role firstname.lastname@example.org should really forward email to his own personal address.