Alright... well, when it comes to Willow, it's not too high fantasy for the setting - it's definitely a good read - but it is a bit too heroic, too epic. These are NPCs, after all; this story threatens to eclipse the players'. I might ask you to reduce the scope, not make it so world-shattering. I do like this story, but it's not what I was looking for. However, something like this has happened in-world, on a more micro-scale.

There is a group that preceded the current players (though larger than the Four, there's a reason for that) - that is called the Seven Stars. The Stars were founded over twenty years ago and disbanded when a mission into the Feywild went horribly wrong - one of their members didn't come back out. If we replace the Spirit Fountain/Rainbow bridge with something less important than the literal Fey Reincarnation Place, the Order of Life and Light with the Seven Stars, and this lich with perhaps a less intelligent, though still deadly, threat that will drastically affect the surrounding area, if nothing else, then it could work. It would also give me a good trigger point for Willow to start remembering things; if she ever meets one of the six surviving members of the Stars, which is very likely, given that one of them is their recruitable ranger, one of them is the father of one and one of them is the mother of another (though this is a secret to most).
Spoiler: The Seven Stars
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I don't know if you need this, but if you need to know their details for the rewrite, they are;

1. Endithas Duren, the gnome ranger. Mid-teens at that point, even though he was about 30.

2. Orion Nailo, a high elf and draconic sorcerer, the leader of the group. He is the one who 'died' - though I reckon he's been magically sealed or somesuch. Elves are ambiguous in age.

3. Natasha Saggitae, a human fighter, blacksmith's daughter. She and Orion are the parents of one of my players (she is largely unaware of the story of the Seven Stars, and believes both her parents are dead). Back then would've been late teens/early 20s.

4. Rimshade McHerald, a human rogue. A past rival for Natasha's affection. He is godfather to their daughter, though the said daughter wasn't born at the point this happened. Late teens/early 20s.

5. June, tiefling cleric. Rimshade eventually 'settled' for her, though in reality, he loves her dearly (she suffers from Second Choice Syndrome, as I call it). At that point, they would've been together, and their son newly born. Late teens/early 20s

6. Orchid Evenwood, a noble barbarian (literally; noble background). Orchid was Natasha's best friend, though they have since drifted apart, in opposing roles to the ones they were born into - Natasha now serves the crown as a knight, Orchid is the second-in-command for the Blackthorn Mercenaries. Late teens/early 20s

7. Calming Skies of the Keen-Eyes Clan, a tabaxi of no particular battle prowess (though might change him to a bard?). He's a lawyer by trade, father of another one of my players, and was essentially their agent, negotiated jobs for them and things like that. Early/mid/late 20s.


As for Fiona, that one works quite nicely. I might reduce the length of her time with Suiamhneas, but this is a good catalyst for her to start changing.