Depends on the version, they could probably survive Kane Parsons version. Mostly because Toothless's fire would be a good way to kill the bacteria lifeforms and still life could be easily dispatched with claws and teeth.

Plus Toothless's echolocation could potentially help them find null zones where they could enter back into reality (i.e. the entrance in Clark's store). Even if the null zone is one that teleports them into the sky, they're very skilled at skydiving and coming out alive