I should have paid closer attention to your question because I asked something you already provided information for. Apologies! :-)
Why do the Veeva teams want to tag the SLN in the Address object? The connector presumably is already configured to update the SLN's from Reltio to Veeva right?
Btw, we currently use the connector in a similar fashion but opted to use a Location entity type versus nest addresses so as a result, our SLN info is stored in a relationType.