Kirin and Pheonix cutscene...???

[Iscah]

Basically, if the screen cuts from "normal gameplay" mode (with UI visible) to a more cinematic presentation, that's a "cutscene" and will be accessible in the Unending Journey. (You might briefly notice the 'filmstrip' icon appearing next to your character's name as you transfer in/out of the cutscene.)

If you just get text conversations on your normal screen, even though it can be really important information, that's not counted as a cutscene and you can't revisit it in-game.

The website Garland Tools has a text archive of the quest scripts - some of them will incorporate dialogue from cutscenes that play during the quest, others will only have the textbox dialogue. Overall it's very useful for going back and checking things that aren't available in the viewer.