Of only that list, I think Brantley will be okay, Francouer will be okay, Melky is pretty good, Nix will give some nice power, Crisp will give a decent AVG plus steals...
Looking at your team, I'd suggest Crisp. He isn't playing spectacular, but he has been fairly consistent all season in terms of AVG. He also swipes a fair amount of bags.
Second to Crisp, I'd go with Frenchy or Melky.
I also agree with the person who said to consider dropping Hunter.Help with mine?
Edit - I like Jon Jay even more than Crisp.