I HAVE POSTED 2 VIDEOS IN THIS SOLUTION. ONE FOR ALL COLLECTIBLES AND THEN THE FIRST ONE FOR CONVERSATIONS ONLY WHICH HAS TIME STAMPS INCLUDED.
NOTICE: Something i have noticed is if you interact with say an item to get you up on to a ledge Ellie will just stand and wait for you to finish doing so and sometimes does not go back to the location where the conversation should take place, if this happens you can use the Restart Encounter in the options menu, just check how long ago it started in case you just want to try again later using chapter select. Another thing is if you go to a location that there should be a conversation with Ellie or anyone for that matter and they are crouching down, this is because there are still enemies in the area. I thought a conversation was not going to start in a large area then found i had still one guy to kill, after that she stood up normally again and the conversation worked.
If you are looking for only one conversation this guide will be handy as you can use the chapter select from the main menu then use the time stamps provided to find the exact one you need in the video which are also in clickable format in the description area of the video on youtube.
The only problem is there is no way of telling which conversations you have had in the game, only the number of them which can be found in the option menu>bonuses>statistics. So if you miss one make sure to take note if you are going to go back to it at a later date.
CONVERSATIONS ONLY OPTIONAL CONVERSATIONS TIMELINE:
THE QUARANTINE ZONE
01. (20 Years Later) Guy and Girl at the newspaper stand / 1:10
02. (Beyond the Wall) Talk to Tess after emerging from the tunnel / 1:36
OUTSKIRTS
03. (Outside) Talk to Tess after waking up / 1:55
04. (Downtown) The Dead Body at the entrance of The Goldstone Building / 2:13
05. (Museum) Talk to Tess before leaving The Museum / 2:37
06. (Museum) Talk to Ellie after talking to Tess / 3:04
BILL'S TOWN
07. (The Woods) Talk to Ellie at The Arcade Machine / 3:18
08. (Safehouse) Talk to Ellie about the Chess Set / 4:40
09. (Graveyard) Talk to Ellie in the bedroom / 4:59
10. (High School Escape) Talk to Bill after finding the note from Frank / 5:40
11. (High School Escape) Talk to Ellie after talking to Bill / 6:16
PITTSBURGH
12. (Alone and Forsaken) Talk to Ellie in the garage / 6:32
13. (Alone and Forsaken) The Dead Body right before you climb over the bus / 6:54
14. (Alone and Forsaken) Talk to Ellie about the writing on the wall / 7:31
15. (Alone and Forsaken) Talk to Ellie about the poster / 8:03
16. (Hotel Lobby) Joel talks about his love for coffee / 8:37
17. (Hotel Lobby) Talk to Ellie about the Dead Bodies in the bathtub / 8:53
18. (Hotel Lobby) Talk to Ellie about the Photo shoot Area / 9:45
19. (Financial District) Talk to Ellie about the Hanging Dead Body / 10:51
20. (Financial District) Talk to Ellie about the Military Prep School / 11:17
21. (Financial District) Talk to Ellie about the Dawn of the Wolf poster / 12:12
THE SUBURBS
22. (The Suburbs) Talk to Henry / 12:41
23. (The Suburbs) Talk to Ellie and Sam about the Ice Cream Truck / 13:14
24. (The Suburbs) Throw a Dart after talking with Ellie and Sam / 13:52
TOMMY'S DAM
25. (Hydroelectric Dam) Talk to Ellie about the grave site / 15:22
26. (Hydroelectric Dam) Talk to Ellie about the horses / 15:54
27. (Hydroelectric Dam) Talk to female sniper / 16:29
THE UNIVERSITY
28. (Go Big Horns) Talk to Ellie about the banner / 16:57
29. (Go Big Horns) Talk to Ellie about the Firefly Emblem / 17:30 (Possible Glitch see comment by Whiskeyjack98)
30. (Science Building) Talk to Ellie about the clipboard / 18:26
LAKESIDE RESORT
31. (The Hunt) Talk with David about the dead body / 19:08
BUS DEPOT
32. (Highway Exit) Talk to Ellie about playing the guitar / 19:31
33. (Highway Exit) Talk to Ellie about the sign on the bus / 20:00
34. (Highway Exit) Talk to Ellie about the ladder / 21:08
35. (Highway Exit) Pet the giraffe with Ellie / 21:56
36. (Highway Exit) Talk with Ellie about the giraffes / 22:23
37. (Highway Exit) Talk with Ellie about your daughter's picture / 23:07
ALL COLLECTIBLESThis video may be from the PS3 version but i guess you will be going for all collectibles and this has them all, jokes, shiv doors, comics,optional conversations,tool boxes, firefly pendants,training manuals and all the other things like notes and letters and will work for the remastered version also. It's a very good guide imo as it shows you the area giving you some bearing as where you are instead of those videos that just load up and have you standing right in front of the collectible without giving you any idea as to where about you are at all, it also lets you know when you are in a new chapter.
I basically pause the video when i see the next location after he shows you what to look for and then when i get there start it and repeat.
IMO this is the best video out there if you are going for everything and just want one single video to play instead of having to constantly load different videos for each item or chapter.
Remember if you do miss something or a joke does not work which was an issue on the PS3 but i have had no issues what so ever on the PS4 but you can always go in to the menu and pick restart encounter or if you want go back to it at a later date you can use chapter select in the main menu.
I used it for the PS3 and i am using it for the PS4 again.
Please give a thumbs up to the creator. I hope it helps.