Unless you're desperate, I'd forget about all of these options, because you could do alot of damage. Forget Hampton and Pavano, because starting anyone, especially mediocre pitchers at Coors is a recipe for a disaster. Gonzalez might be a decent option, since he has pitched the best of the DRays starters and faces two losing teams, but he might get zero run support, meaning that the chance of 2 or even one win isn't great, making the possible ERA/WHIP hit not worth it.
Garland has been OK overall this year, and probably is the best of the options, since he is playing for a team whose offense is on fire and has a good chance at reeling in the two wins. However, it's still risky to use him against Texas, who could easily light him up nicely, although the start being in Chicago makes it a little less risky. Weaver has been too inconsistent and all over the place this season for me to recommend using him against anyone other than the Tigers. Yes, he could be awesome and will likely get the run support, but it's not worth it.