Dual whelding, no. But, a whip is a neat tool for more than combat. It still requires a weapon prof though. If the human gets an extra, extra bonus feat, perhaps something like the regional feats from 3.5, it'll open Justin up to be a bit more versitile.
As far as the teamwork feat goes... someone mentioned a flanking thing, but if not, it's not a big deal. Not everyone in the group has to have a teamwork feat.