This The Last of Us 2 Walkthrough for Chapter 4: Seattle Day 3 - Infiltration explains how to find the people you're looking for and lists all the collectible locations/notable areas including just 1 Journal Entry.
There’s a door ahead but it’s locked. On the pier, move to the far right and approach the gate. Crawl through the hole in the door. Climb up the high voltage machinery to get to the top. Drop down into the aquarium. Turn on your flashlight to see things more clearly. Along the perimeter of the tanks, look for the orange dolly, leaning against the blue tarp. Jump over that tarp and squeeze through the wall ahead. Move forward and on the right, there’s a hole in the concrete you can crouch through. Walk through the shallow waters and climb up the ladder ahead.
Drop down to the yellow bin full of clothes/fabric. Be sure to loot the area (including the locker for some supplements). Go through the open doorway. The next door is locked but you can continue on your path by turning around and climbing up into the vent. You’ll drop down and have to mash square to fend off the dog attacking you. With the dog dead (RIP) walk into the room ahead. Loot the surgical room. The double door ahead is locked so go through the open doorway on the left. Continue into the next room. It’s a kitchen/break area with red rugs and sleeping bags.
Journal Entry - Owen Moore Firefly PendantOn the left of the refrigerator is a duffle bag on the floor. Interact with the duffle bag to examine a pendant and sketch it in your journal. Loot the table before exiting the room and going directly to the door with the crab on it. Enter it and a cutscene will play, there’s a bit of interactivity here so don’t put down your controller. You’ll wake up back in the theater. Walk to the main stage to talk to Jesse and Tommy. Another cutscene will play afterward. This leads into the next section: The Park.