That Jesus story comes from Rabbi Onkelos, a Roman convert who performed necromancy (!) to summon Jesus and ask questions about the afterlife. Apparently Gehinnom as described by the conjured spirit was indeed reserved for Jews who sinned; I think the unrighteous gentiles (not the Noahide) simply stop existing. They also got Shabbat and Yom Kippur off (I wonder if the summoning ate into Yeshua's break time.)

The Talmud is fascinating but pretty wacky.