I love Warrick Dunn, but we already signed Fred Taylor for basically that same role. Kevin Faulk's still a heckuva good role player, Sammy Morris is pretty good in his own right, I don't think they've given up all hope on Mauroney, and I wouldn't be surprised to see a RB get drafted.
So, I just don't see where Dunn fits.
As to Brooks, he's really nearing the end. If he wanted to come aboard at a one-year, vet min contract (loaded with incentives), sure, bring him to camp. But, I'd be shocked if we don't leave draft day without an infusion in the LB corps, and Brooks doesn't really help the fundamental issue of needed to get some young legs in there.