Character B is still a struggle and I think I figured out why: I'm not letting him be himself. This is a character who represents all the things we wish we could do, the one who has no boundaries, no tolerance for bullshit. He's not a wild child, but he has no patience for stupidity... or patience at all for that matter.
And here I am, trying to shove him into situations where he just doesn't fit - situations full of rules and regulations. This is intentional of course, because I need to make him suffer and cause conflict. However, Character B is not bouncing back, which is what he should be doing. I'm not letting him bounce back, because that would cause consequences that would create strong deviations from where I wanted the story to go.
It's interesting that Character A fell well into the outline, but Character B is having a tough time. I guess "To Outline or Not To Outline" really depends on the type of story you have.