You can't use $_GET[] to get the friendly name, since it isn't in the url.
You would have to put a recordset on the page and filter it with the $_GET["incentives"] id value to display the associated incentive name from the recordset returned.
You can pass multiple incentives in the url, but you would have to pass them in an array with brackets [] like:
page.php?incentives[]=11&incentives[]=22&pedigree=&credentials=&sire=&Search=Search
Then you could create a recordset to filter based on the array to return the incentive names from the url and use a repeat region to show all of the incentives from the recordset.