Not quite - the hydroplate theory [have either of you even read it?] also posits the ripping open of the Earth’s atmosphere and causing the ice age. So the heat was offset by an immediate cooling. It’s possible there was a massive loss of sea life but the land, air and sea have been re-stocked fairly well considering a massive break in the Earth’s crust circumnavigating the globe.
That doesn't mitigate the damage do to physical pounding from the water. If you could attain "immediate cooling", then you've lost one of the necessary conditions that have been used to explain the fossils. An atmosphere cold enough to cool off that much hot seawater that fast would have frozen everyone and everything on the ark in no time. Every explanation seems to involve some nearly impossible physical extreme that's incompatibly with the explanations of other events supposedly happening at the same time.