When I attempt either of those options I get the following errors: 

defining the .schema(explicit_schema) returns the same result of having the headers as the data for every row

OR

[Databricks][JDBCDriver](500051) ERROR processing query/statement. Error Code: 0, SQL state: null, Query: SELECT * FROM edl.test_table WHERE 1=0, Error message from Server: Configuration header is not available..