Most of the endings relies on Shakti's arc (which relies on the others), so having a save before invading Renrick will help you to see 4 of 5 endings.
Saving Fanielle require to throw a feast once by week (no more no less).
Circle has only one ending with light variations (there is no real replay value to see it)
Sorority is more tricky as the true ending is meant to be hard to find.