Thanks for the help on mine.
I wouldn't do either of those trades. In my league, at least, Slaton went before Manning, and Jennings got picked right after Manning and well before Ocho. It's just my league, but I think that's a pretty accurate account of their relative worth. (Slaton > Manning = Jennings > Ocho).
If he wants Jennings, let him trade you Manning straight up for him. Or counter with Jennings + Hill for Manning + Bradshaw.
If he really wants Slaton, I'd counter with Slaton + Hill for Manning + Washington. Or, with Jennings + Hill for Manning + Bradshaw.