Hi Jason,
Welcome to communities,
>Does OCUM 6 and up act as an SNMP traphost or does it exclusively use polling to discover events on the filers?
OCUM6.X uses polling to discover events on filers. The polling interval is 15 mins. So after every 15 mins clusters are polled and events are generated.
AFAIK Sending Filers SNMP traps to OCUM 6.x isn't available now but might get added in future releases
hope this helps.
-Srinivas