It's not surprising to find the last two Missing Persons in this area. Take note that after doing some campaign missions here, the marker for the bodies won't show up in the map anymore. In that case, refer to the map screenshots below.
Annie Nelson
Head to the Crazy Moose in and follow the dirt path, preferably with a motorcycle to the west. You'll find a cabin in the middle of the path. Head inside to find the body and the audio log.
Michelle Strauss
The next victim is found inside an abandoned railcar in the northwest corner of Pawnee. It is found up a hill. Examine the body and the audio log nearby.