Reconcile MakeAuthOptions and PopulateAuthOptions

These functions are used in separate places and appear to have similar intent, but while PopulateAuthOptions preserves the existing options its given, MakeAuthOptions discards them. This seems incorrect on the surface, but there may be reasons why it behaves this way. Further investigation is needed to determine if MakeAuthOptions can be changed to preserve the options passed in and/or the two functions could be merged.