A few thoughts from reading the last few pages:
Singletary was a 3rd round pick. He's started 40 of 45 games over 3 seasons. That's good value for the 74th overall pick, especially considering he has one more season on his contract.
I don't view James Cook as more than a 8-10 touch a game weapon. As to comparisons with Thurman Thomas and Devin Singletary, Thurman had what looks like a sturdier frame than Cook and had nearly 3300 touches in his career. Singletary whose nickname is "Motor" is 5'7", weighs over 200 lbs and can squat 550 lbs.
Cook is both taller and lighter than either Thomas or Singletary and appears to have a slight build.
I think Cook can be an excellent weapon for this team but I don't see him as a starter or a workhorse.