I don't think there are any Maldives liveaboards offering 4 or 5 days. i'm pretty certain that your options are 7 or 14 days.
I've done a couple of them
Sea Spirit
Plusses: superbly well organised diving, great dive guides (david & Tracey), just 12 divers on the dhoni.
Minuses: Nitrox very expensive, boat a little tired, food ok ish.
Nautilus2:
++: huge cabins & best food ever on a liveaboard (even compared to Aggressor fleet), free nitrox.
--: diving not so well organised, 24 divers on dhoni does not make for rapid descents in strong current.
Both of these boats start finish in Male. You might want to look at Monsoon. This starts/finishes from Kuredu resort & so might fit your timetable better. ie you can spend the last day in the resort not in Male harbour counting down 24 hours before boarding your plane.
I hope this is helpful
John