@last third
In my opinion You are right. Due to the hard OEI landing in the water, the belly ore the Radardome must have been damaged and the H/C took water. Check the high waterline just before the MR struck the water.... And in addition the extended Landinggear also made an SingleEngineWaterTakeoff ( a procedure like with a seaking or S61 ) much harder or even impossible.
skadi