Oops - I forgot to add that at step 7 I added the following metadata:
<tables xmlns="http://labkey.org/data/xml">
  <table tableName="ListB" tableDbType="NOT_IN_DB">
    <columns>
      <column columnName="Foo">
             <fk>
                   <fkFolderPath>/Main</fkFolderPath>
                    <fkColumnName>Key</fkColumnName>
                    <fkDbSchema>Lists</fkDbSchema>
                    <fkTable>ListA</fkTable>
                    <fkDisplayColumnName>Name</fkDisplayColumnName>
                </fk>
            </column>
    </columns>
  </table>
</tables>

-Will