In order:
- The answer to this question is on Page 14. "The Replay marks are unique to each enemy and do not apply to the enemy type as a whole."
- Collapsing Wall is in the Quickstart. It and Pit Trap have both been omitted from the Core Rules - this is a mistake that I'll fix with the next update. The yellowing skull isn't an item that needs a description - it's simply a yellowing skull. The Soulless Curse has also been omitted from the document and will be fixed with the next update.
- Yes
- Not unless they have enough Replay with that enemy to bypass the enemy entirely, though you should of course feel free to houserule this is you don't like it
- Whatever you want it to mean - it's left to the player and the Guide to interpret