The fact her only current tag affinity is with Joseph kind of disproves this, though...
Men, not a man. ;)
Sae is a robot.
I know this is WMG so this doesn't need justification, but I'll try anyway! It's a bit odd how she just went along with Miyu's orders to go and work for Ken and has no problems with obeying Ken's orders. Simple reason: She was programmed to serve Miyu until a new master was appointed. That new master was Ken. As for why she's a miko, surely even Robot Religions need holy people (or should that be holy gynoids?), right?
Black Hole are from an alternate reality.
Think about it.
How is this "wild" or "guessing" exactly?
Black Hole are NOT from an alternate reality.
They're actually space ants, testing the world to see if it's safe to make first contact. Alternatively, this the UFO Ending for the Black Hole event.