I'd let Hammonds walk and would have no qualms about playing Guerrero in CF, esp because he is making league min. His def (IMO) will be just fine.
Eckstein is a nice player, but I don't think I'd ink him LT for the money he is going to want. I'd either trade him, or, sometimes if my team is in a good spot financially, and I'm not stressed for payroll the coming season, I've arbed him in his last arb elg year and just taken the comp picks the following season when he walks if you're not able to trade him. Although, if you can use that $7-8M that it will take to keep around for that last year somewhere else, I know thats hard to do.