Flashbacks in Wa-no-kuni

It's pretty obvious that we will get to see a Wa-no-kuni [~island of peace ; the 'home'-island of Samurais, like Momonosuke, Kajuro, Kin'emon and Ryuma]-arc, so I thought about which flashback might be shown during that arc. But instead of keeping them in my mind I wanted to share my thoughts and gather some ideas of you guys

Which flashbacks I expect/would like to see:
•Some Ace and Oars Jr.
•Maybe more Majins (other than Oars Jr.)
•The prime of the Samurai Ryuma
•How the Marines tried to...

Flashbacks in Wa-no-kuni