From what I remember I think you've pretty much got the timeline right. Though I don't think exactly understanding the details is critical in any case.
Also something worth mentioning is that I think the first game was originally intended as a standalone game, which I bring up to say that everything needed to understand the backstory of the first game should exist within the first game. The later games are technically sequels, but will mostly address a new story rather than plot points from the first game--think Trails in the Sky vs. Trails of Cold Steel. (However Mask of Truth is a direct sequel to Mask of Deception, more analogous to say Cold Steel 1-->Cold Steel 2)
I never cared much about Kurou or Oboro. (Or the archers but lol.) My clear favorites from the first game are Hakuowlo/Eruruu/Aruruu/Benawi, but other than the ones I just mentioned I think I like pretty much everyone. ---
I didn't do guru this year but azuarc can be in my sig anyways.