Ending 4 might require you to have at least one of the talismans, since you get +5 Harmonized Qi only when you get all ten of them installed, as a "you started the correct thing, but you're not done with it" ending.
...I do suggest backing up the current savefile first, just in case I am wrong. I am not the dev and I am just guessing from what ending 5 says lol.