1B/2B/3B Daniel Murphy, 3B Zach Lutz, OF Matt den Dekker, RHP Kyle AllenSome reasoning for the madness:
For the Mets: They get Ricky Nolasco, a high strikeout, low walk pitcher who has big fly ball tendencies and has two more controllable years left. Pretty much the model target for the Mets. Bonfacio would also help as a defensive replacement/ fourth outfielder as well as provide some MI depth, and a halfway decent backup for David Wright at third to give the guy some rest.
For the Marlins: The MO for the Marlins is never usually to try and acquire high-octane prospects, as their player development system is stellar and always filled with talent (recent examples of home-grown awesome are Logan Morrison and Mike Stanton, others include Josh Johnson and Dan Uggla). They usually head after players near the big-leagues or in them already, examples including trading Dan Uggla for Mike Dunn and Omar Infante, Carlos Delgado for Mike Jacobs, Josh Beckett for Hanley Ramirez (there were many others but that was the main idea), D-Train and Miguel Cabrera for Cameron Maybin and Andrew Miller, etc. etc.
Daniel Murphy and Zach Lutz bring them immediate candidates to play third or second for them at the big league level. The Marlins have never been too intent on finding nimble fielders, and seem to like guys who can rake rather than play the field gracefully (such as Dan Uggla, Hanley Ramirez, Logan Morrison, Miguel Cabrera). Murphy has the ability to hit pretty well in their lineup plus possibly fill the void at third base for the Marlins, and his defense at third is decent, and at second should be better than Uggla. Lutz also seems to fit with their mantra on acquiring players. He already has some raps at AAA and seems to rake at every level, and could be a possibility to fill the void at third (or even second, but I wouldn't think he'd do too well there). Den Dekker also fits into a Marlins-y scheme. The Marlins, no matter how poor their defense is, always seem to have a good defensive center fielder, with their history including Juan Pierre, Cameron Maybin, even Emilio Bonifacio at times, as well as many other pure defensive rovers. Lastly, Kyle Allen appears to fit in with their pitching philosophy. He relies mostly on his fastball, gets some Ks but keeps the ball on the ground. More of a throw-in really, but I can't imagine it'd hurt.