Kamehameha as soon as Atheon shows up; game over.
And since Goku and Vegeta don't originate from the Destiny universe, I'm assuming neither one has Light nor Darkness. And Guardians can only be brought back so long as they have their Ghost and aren't in an area filled with the Darkness. If their Ghost is killed, they're finished.
English
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Instant transmission -> Touch Atheon -> Instant transmission into Crota's lair bringing Atheon along. Goku watches.