Here is a video guide with English commentary!
Here is a playlist of guides for this game!https://www.youtube.com/playlist?list=PL-HeW6XkKdUJNaduS4UQz...
There are 6 optional collectibles in Episode 4: Faith. Each optional collectible will unlock a specific achievement / trophy. If you have completed the episode, you can go back to specific chapters in collectible mode and not affect your decisions in the episode. Here are the timestamps for the collectibles:
0:34 - #1 A New Perspective
1:12 - #2 Lone Wolf
1:56 - #3 Amazing Grace
2:47 - #4 Promised Land
3:35 - #5 All Sinners
4:11 - #6 Heaven & Hell