(blocked) asks:
> How would Delenn know about B5 declaring independence, and know
> that they needed help?

Real simple. Lennier was still on-station. All she had to do
was check in with him en route and find out. Also, she went to the
council for the purpose of getting military support because she knew
heavy stuff was coming down, in one form or another. Knowing that "the
humans are fighting one another" as she said to the council, it's
evident that if they didn't come to B5 that day, they'd come shortly
thereafter.

So no, not a major error at all.

jms