And there's four people, on average. It works out to be only slightly tougher than a level appropriate encounter, putting it just on the higher end of CR 4, WHICH HAS BEEN MY ENTIRE POINT.

If you'd like this in other, clearer, language: the Ekolid is appropriately CR'd, if you are willing to accept that some CR 4s are better than others. If you are not, then make it CR 5 and move on.