Daydreaming about fun little post canon extra information for my little bloody mary daemons au fic series, but probably won’t actually get around to writing more installments for,,
Grace wouldn’t live longer than a normal human lifespan. Even with Erid’s technology, their world would still slowly wear him down, and age and complications from going malnourished for so long would still have an effect on his health.
Laika however, is no longer solely bound to Grace. The Eridian soulmate tether Grace and Rocky formed could theoretically keep her around as long as Rocky lives, so while Grace’s physical body dies, his soul would be able to go on living alongside Rocky. I’d like to think that over time, as the bond deepens and gets stronger, Laika would become increasingly Eridian-like to the point where she could survive outside the dome if she chose to, while retaining the mostly doglike features.
Simon on the other hand,, I don’t think he’d ever really get to the point where he’d trust an Eridian enough to share fragments of his soul with them, especially considering how messed up the Light and the COI had made Félicette (who eventually chooses to keep the nickname Grace gave her, versus the name Mangrove, which the Father in Eden chose for them). I think he’d be concerned that the exchanging of fragments of her could harm Rocky and Adrian, the two most likely candidates for Eridians that he’d get close to and trust.
But at the same time he doesn’t really need to ensure his soul can stick around after his death to keep Grace-Laika and Rocky company, because he’s already got some tree freakiness going on in the au. Being a meat tree for a while and retaining the tree-ness enough to grow twigs and leaves on occasion would also be enough to give him a tree’s lifespan. Simon lives long enough in his human body to roughly match the lifespan of Rocky and Adrian, and Grace-Laika by proxy. And when that body does inevitably fail on him, the tree bits fully take over and grow Erid’s first tree.
Some of Rocky and Adrian’s pebbles take over tending to the biodome, which slowly becomes home to a forest of calcium and iron rich trees, which act very similar to that one massive aspen colony that is all technically one organism. And because I’m a big enjoyer of the ‘Eridians turn the biodome into a Grace memorial and museum’ headcanons, I’ll just borrow that and glue it in here. The forest is something like an ‘Earth’ nature reserve.
And if you’re lucky, and you’re nice to the forest, you might just catch the echoes of a leafy margay purring in the branches, or the distant calls of a barking dog out in the waves, or barely audible Eridian singing when the sea air runs along the cliffs.
Maybe when Simon was remade by the Light, pieces of that divinity were left behind in him. And maybe, when his and Grace’s and Rocky’s time all run out, those fragments of divinity immortalize all three in the place they spent the most time together.