- Just mistaken identity and Baldur had no idea of Kratos' history - Odin would likely have known of Kratos, so it's possible he knew what would happen (to Baldur) and is trying to control Ragnarok?
- Time progresses differently in each realm but certain events are fixed. I don't think the timeline will make sense until the 3rd game.
I watched a few interviews from C.Barlog (on YouTube) and he hinted that Mimir has been mistranslating what the Serpent has actually been saying; Mimir probably has his own agenda, likely serving another set of gods (Mimir mentions his homeland is Egypt?)