I think blowing up means keeping Garnett and Allen as expiring contracts (unless another team gives you bigger expiring contracts and hands you a draft pick, probably a second rounder, as compensation for saving them extra million or two). The players you trade are, in order of likely desirability assuming they are all 100% healthy, Pietrus, Bass, O'Neal, Wilcox, and Dooling.
Then, I fill the bench with D-Leaguers. Blake Ahern, Manny Harris, and Elijah Milsap, if they are still available, are the guys on my radar.
I think you are so unlikely to get something for Garnett/Allen that the better option is negotiating a buy-out that lets him go to a contender of their choice and take your mild savings in salary and luxury tax, if that's what they would prefer. Keep 'em and trade 'em are not the only two options.
With Pierce, I think you wait until the off-season to trade him. if that's what you want to do. I'd be looking at teams that were angling for Dwight Howard, missed, and want something to show for their efforts (assuming D12 doesn't come to Boston).