If I am correct and there only needs to be one, what is the best way to remove the extraneous ones?
You'll have to stop the server, slapcat the cn=config DB, delete the extra overlays, and then slapadd the cn=config DB back in. I would suggest adding logic to your process that checks for the existence of the syncprov overlay prior to attempting to add it to the stack.
--Quanah -- Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: <http://www.symas.com>