If Galactus is at full power then Thanos might as well go to the otherteam and they'd still get owned. Rune King Thor is at Sky Father Level and therefore way above both Pre crisis supes and Thanos but still nothing compared to the Big G. I don't know why people (including me) say even pre crisis Superman can effect a battle with Galactus. Superman is more on a level with the heralds, hell, post crisis Superman WAS a herald. No, a fully powered Galactus would own them all, and very easily, he's on par with the Abstracts and the strongest Celestials. The other three don't have a prayer.