As far as our signings go, William Gay should not count against us as he was cut. Resigned players like Foote will not count. I don't know about Gradkowski (he may count).
Keenan Lewis should be a fifth round comp pick if he starts every game. Adam T suggests that players who received 4.5 million per year will be worth 5th round comp picks in 2013. Lewis's contract averages 5.25 million per season. In fact, guys earning 5.5 million per season are anticipated to be worth a 4th round comp pick (for this draft). So, Lewis is close to that. Still, I think he'll just fall short. He should easily be a 5th rounder.
So right now we have a 3rd (for Wallace) and a 5th (for Lewis). Gradkowski could cancel out Mendenhall. Any additional 6th or 7th rounders will come from contracts signed by Starks (he could get a deal for 2-4 million, I believe), Hampton (someone will pay him vet minimum), Legursky, Mundy, and Sylvestor (minus any other FAs we sign who were not cut). You can only receive a maximum of 5 comp picks.