it sounds like they (CPU, Memory, interfaces) don't show up in Orion System Manager. so, is F5 only using SNMP v1?
if you have the verified F5 OID info then you can use Univeral Device Poller. when using UnDP you can create a group with those F5 OIDs for CPU, Memory, etc. then in UnDP assign these to your node. and it depends on the values you get back, you may have to use UnDP TRANSFORM to translate the values to Bytes or Percent or whatever.
then go into the Orion web site (and drill into that node you assigned the UnDP poller) then you can EDIT those custom pollers for presentation.