Major Spoilers for all Expansions - Some general things I didn't understand

[Alleluia]

If we're on the topic of things we still don't understand:

1. Are Darkness and Light elements, just as Lightning, Water etc. are? If so, what's an example of Astral Light and Umbral Darkness?

2. There are three types of aether in a person, it seems: corporeal, soul, and memory. Can you create more memory aether by making more memories, thus a longer life adds more to the lifestream than it took when it dies?

2a. Could this have been how the overall amount of aether was supposed to grow and increase in the original ancients' plan to "raise up life to harvest for Zodiark"? Cus the lifestream seems to be a closed system. Since the aether present on Etherys post-final days came from Zodiark in the first place (he'd restored life to the world), where else would you get the extra you'd need to sacrifice back to him to get something new? If you aren't adding new aether somehow, then you're just shuffling the same finite amount about, and if that's it then you'd have to give up part of the planet's ability to sustain life for that second sacrifice no matter what. Cus you are just sacrificing back part of the aether he gave you to fix it in the first place. If no new aether is found or created, equivalent exchange (and thermodynamics) isn't respected and that does my head in. lol