Okay. Couple points...
Schilling's first start will be on July 31st, ie Theo will have ZERO time to determine if he is ready or not. And if the yankees are still trailing you in 2 weeks when the waiver wire opens, you better believe nothing that can help you will get by waivers. So you have to consider Schilling a wild card.
In terms of Bonds, the Giants wont put him on the market prior to him breaking the record and with his knees and ankles barking, he might not break it within 2 weeks. Hence, unless he gets hot, the only way he moves is if he makes it through waivers, and that wont happen.
Sosa has been clubbing this yr. His average is crappy, but his power and his RBI totals will garner a lot of attention in what promises to be a pretty s***** deadline. I would assume that the Rangers will get something good for him, so not a C level prospect, IMO
In terms of Wheeler, he is their closer for the time being and is s***ing the bed. But at 29 and coming up on Free Agency, he should be available. The problem is, are you willing to send them something of value (as you said a B level or a Masterson level prospect) for a guy who's era is above 5 right now.
I terms of bringing in Buchholz, by all means, give it a try. But I think Theo is smarter than that, since he knows that Buchholz could be an ace for yrs to come and wont sacrifice his learning curve and confidence for one season.