3) Dawn is Eos, Day is Seraph.
6) The Aetherflow Gauge is renamed the Strategem gauge, and Libra is essentially a reskinned Aetherflow that better fits the Scholar's theme and job flavor. It still restores MP and grants a full stack of Stratagems.
As for Coalescence during Day Phase, that's a great question. The abilities should do a better job of synergizing with each other, so Coalescence during Day Phase should return the fairy to Dawn Phase and grant a full stack of Stratagems. That way, if you plan it properly, you can get more Stratagems from "eating" Seraph before she leaves.
Another possibility – a trait that allows Deployment Tactics to grant an instant Bane effect to Biolysis. They can even use the old Bane animation, since Summoner doesn't do DoTs anymore.
