Is this a PPR league? A keeper league? If it's a PPR or gives points for returns, or both, Darren Sproles is pretty valuable. I question the wisdom of giving up a top-flight wideout in Jones, a good TE in Gresham, and a valuable RB/flex in Sproles, along with a flier on Brown, to receive a very good to top-flight wideout in Nelson, a good TE in a heavily-saturated passing attack where he may not receive as many targets as Gresham, and Michael Crabtree, who comes with all of his inherent question marks.
The second trade doesn't accomplish your goal of freeing up roster space and Sidney Rice is probably not going to produce like Dwayne Bowe. Gresham and Davis seems like a wash, though I'm generally leery of Redskins in general, and having a rookie QB doesn't change that for me.
I don't get why you wouldn't just drop Wilson for Smith in this case.