I had not thought about the need to name the fields and checkboxes as I have not had to do this before - but to name them, the convention I would follow would be something like this:

LoanTypeConfirmed (checkbox)
LoanTypeDate (field for date auto-post)

And then as to date storage - I would create a summary section on the document that would list the tasks and the dates.

Task (Heading) Date (Heading)
Loan Type Confirmed Date from field listed above

Martha