Kaede, Kohaku, Kagome's family remember who Inuyasha and crew were. Kohaku even recalls his time traveling with Sesshomaru. So there hasn't been a memory wipe for everyone. Seems to only be the case for the three kids which probably has something to do with their pearl.
Sesshomaru left his kids in the wild when they were newborns, according to Kaede. But her perspective may be unreliable since they couldn't survive on their own unless someone took care of them. Raises further questions of who is the mother and what happened to her. What was Sesshomaru's motive. "Rite of courage and cowardice" feels too simple for him.
Setsuna knew who Kaede was as she asked to stay in her care. As if someone directed her there. Someone had to be helping those twins along the way. She's also shown to have Sesshomaru's fur thing before she goes to Kaede.
Towa's power was unlocked after the pearl shined, so it's clear that the source of their demon power comes from that. Which then makes sense why demons want to take it from him. Similar to the shards.
Someone appears to be inside the tree of ages. Could be Kagome or Rin. Can't say I like the idea of either character being trapped somewhere, but maybe its not actually them and is some sort of spirit. Kikyo is also making an appearance in some form next episode with a task for the kids. Will be interesting to see how that goes.