In 4x06 - Into the Fire, Ivanova was quite worried that she'd miss the final battle because she was out with Lorien hunting for first ones. It seems to me, however, that Ivanova's presence was absolutely essential.
If she wasn't at the battle, Lorien wouldn't be there, either. If Lorien wasn't there, he wouldn't have been able to share Sheridan's and Delenn's dialogs with the Vorlon's and the Shadow's, respectively, let alone pull them out when such action became necessary.
Also, although Lorien told Ivanova that Sheridan's plan was, quite possibly, foolish, Lorien seems to have been fairly confident of a successful outcome, all the same. If he wasn't, rallying all the first ones up would have just been a waste of time, it seems.