First of all, Escobar is no longer the Blue Jays closer; Cliff Politte is. Escobar has been moved to the starting rotation.
Out of the other three, Mike DeJean would be my first choice. He did pick up 27 saves last year with a fairly decent ERA and WHIP. He'll get you 25 saves or so, even with the Brewers. Normally, I'd say take Looper over DeJean, but with the management change in Florida, Jack MacKeon is rumoured to be an advocate of closer committees, meaning that Looper might not get as many save chances.
Carter would be the last choice of the three because he has no closing experience before this year and because the DRays are just as bad as the Brewers and Marlins, if not worse. Also, if John Rocker ever gets his form back, he might well wind up as their closer.