Surfer has rarely lead.... Ie. Adam warlock or thanos or ff4 etc tell him what to do.... One if the few times he's lead is against tyrant when leading the othe heralds...
Superman and Thor are both huge morale boosters when on the floor. Both have charisma....
However it's superman that everyone... Including green lanterns look to save them and lead them...
Powerset wise I'd say surfer But base on the op I gotta go superman.
Supes would be a good leader... and the normal people are total gay for him. Would be a great morale booster, along with his amazing PIS whenever there is something no one else can possibly do, for some reason the writers make him able to do it.
Then again... Surfer came knocking on your door I would shit my pants just a bit faster. But just power level wise i mean SS can just do so much more. I would def choose SS as my powerhouse but Supes as a figurehead.
If I were building a team that's in need of a powerhouse I personally would choose Nova. He was the leader of the resistance in Annihilation. He even led beings that were more powerful then him.
But for the sake of the thread I'd probably pick Supes. The other 2 are more powerful/versatile but Thor comes across as a bit of a tool and the non-Galactus influenced Surfer is too much of an ideologue.