I’m pretty sure Lehvak-Kal could make a comeback, provided it wasn’t crushed between Aqua Magna and Bara Magna when Spherus Magna was reunited.
I know Greg’s said that it would burn up in the atmosphere, but Lehvak-Kal’s vacuum powers should be able to prevent that, as well as provide upwards lift to prevent high-velocity impact with the surface.
The same could also be said of the Tahnok that Nuhvok-Kal sent into space; they would presumably be fireproof against reentering the atmosphere, and at least some of them should have krana Vu.