I'm sorry, Teri, but I never saw that you responded, before my input here nearly two hours ago. Oh, is that your "other" username, regarding the QB Online? Yes, QBO does not handle Job Cost tracking for Payroll. It is implied, in Timesheet entries, but not to the financial reporting.
Everything I show is even in QB Pro; any of the Desktop programs do this fine.
1. In Preferences and Payroll you access Employee Default, which is then used for all New Employee Names; so, yes, you also need to Edit and Update existing Employees for that setting.
2. Using Timesheets. Everything starts with Timesheets.
3. I showed that image as an attachment in one of my previous responses here.
4. Yes, that is it. Same as 3.
5. My Favorite Function = Multiple Names. Please see this reply's Attachment.