Your TDC settings look correct for forcing the use of SQLColumns, but your vendor name and driver name look bogus. You should check the Tableau log files to determine if your TDC file is actually being applied to the connections you create from Tableau. You've likely already seen our KB article, but here it is again for reference to help you identify if your TDC changes are actually being applied: http://kb.tableausoftware.com/articles/knowledgebase/customizing-odbc-connections
Another point is that Tableau tries not to issue 'TOP 1' or 'LIMIT 1' queries for retrieving metadata. Those queries are likely capability probes that Tableau performs upon connection to determine what flavor of the syntax is actually supported. The TDC documentation describes how to hard-code certain capabilities so that Tableau won't issue those probes, and you can also turn off all capability detection probes.
I hope this helps,