Some of those leaks could be leaking air into the filter while the pump is off. And yes, there is an o-ring in the drain fitting.

There also MAY be a drip from the "Inlet" part of the filter where a black connector on the filter joins up with my white PVC piping. Seems to be a small wet area where they connect.
That sounds like the multi-port or push-pull valve and is a common place for some leaks. They too have gaskets/o-rings that can be replaced.