Filtering Resolved Data
In my testing it would seem that you can only filter on primary data within a collection, not anything you can also Resolve in. Basically SOE's code will do any specified filtering on the requested collection, and then pull in any 'resolve' data that matches what you get. The documentation doesn't reflect this limitation.
I was wanting to grab all online characters by Resolve'ing in the world and online_status collections to a character query, but then limit it to ones with online_status > 0, but it just didn't do any filtering (note I did use c:limit=5 in these tests to not attempt a humungous data pull each time). Filtering with primary data within the character collection works without problems (i.e. I could limit it to my character with ?name.first_lower=athan but replace that with online_status.
An example which doesn't work:
In fact it takes quite a while due to no effective filtering. You don't even get ANY characters out of it, i.e. failure to find the field you're trying to filter on at the time means no data ever matches.
Compare to this that does work (all I changed was online_status=0 to be name.first_lower=athan instead):