Took me a while too but I found em all.
One is in a cave to the left and up a bit from the cave where you pull one of the levers. He has been captured by Nuzleafs
Another is in a building being held hostage by a Team Meteor member. You can find the entrance by heading up from the PULSE Machine and then there is an entrance next to a box on the right.
And finally there is a rather sad find above the survivor guy who heals you. Head to the building where the guy with the supplies is, head outside and enter the side of the building instead. there will be a Growlithe looking down a hole. Talk to it a couple times and it will move. Look down the hole and you will find the body of a poor police officer who fell to his death.
Hope I helped
