1. Sphene is playing god editing peoples memories. If you listen to the guy in the first zone he tells you this is how he wished his love life had played out and not how it actually did in his real life. Also Sphene was actually kind and cool not some Skynet killer bot.

2. They make it clear that the aether being used to maintain the Endless some of it came from killing Wuk's people. They are vampires.

3. Why can they not just write it down? It would probably require more space than exist on the face of the Earth to write down all the little details contained in just one persons life. There is a reason she was trying to take over entire reflections just to maintain what you saw.