I certainly think you could put one on floats ... but not stock. It would need some help to lower stall speed and correct engine torque. Basically you had a SMALL airplane with a HUGE engine ... taylor-made for problems on water. I think maybe a floatplane-specific wing-fin-rudder coupled with maybe a ventral fin for assist.
To me, it would be easier to design a floatplane fighter from scratch than to adapt a Bf 109 for it, but others might feel differently. I am remimded of the relatively large number of takeoff and landing accidents the Bf 109 experienced and think it might not have been as fatal in a BF 109 floatplane, but surely would have resulted in the loss of a lot of 109's had the tendency to swing on takeoff not been cured with the new floatplane setup.
I'd much rather have adpated an He 112 with more span than a Bf 109.
Still, it DID have a relatively low stall speed with slats out and flaps down ... it was in the 78 mph range, power-on. You'd need smooth water for it ... but if they can get a Schneider cup racer airborne, they can do it with a Bf 109. Nobody ever tried to FIGHT in a Schneider Cup racer, though ... they could barely SEE out of them.