Hi Michael M My experience with Echinopgon ovatus & E. cheelii is that they can look very much the same. How do you know this is E. ovatus? My sightings to species of Echinopgon have been verified by ANBG.
Photo 4 to me indicates that this specimen is rhizomatous (ovatus) rather than arising from a tight tuft (cheeli) also the seed head does look smallish (but not enough to confirm species on this character alone)