Well Hulk strength feats are impressive such as taking down a building sized Leviathan with a single punch. Then pulling another away from a building in mid air. But he was overpowered by the Chitauri lasers. And the Chitauri were defeated by a nuke. Hulk also beat the abomination who seemed to be alot stronger than he was due to his whole Anger=Stronger deal. AoU he survived without a scratch being slammed through an unfinished building and got up like a minute after. But he was knocked out by a Sucker Punch from Iron Man.
Granted it was to the temple, a part thats weak on any living being and usually knocks them out. But I'll still count it as a vulnerability.
Supermans feats include lifting and pushing trucks like play things. Dragging a massive ice breaker ship through a frozen sea. Being thrown through several buildings, and into the vaccuum of space without so much as a scratch. Surviving a nuke after a kryptonite beat down from Batman and tossed around by Doomsday. Then resisting his weakness long enough to carry it to Doomsday and shove it through his heart despite having himself impaled as well.
No one in the Marvel Universe knows what Kryptonite is so they cant get it. Wonder Woman was able to survive Doomsday tossing her around and cut off his hand Skywalker style. Batman cant do jack **** to people like Hulk, Thor and Doomsday as we saw in BvS he barely survived DD attack running away to survive.
Thors hammer is magical and I can only assume so is Scarlet Witch so she and him could maybe effect Superman if he has the same weakness to magic comic Supes has. If not Thor was able to summon enough lightning to take down like 3 Chitauri Leviathans. Took sown one with the Hulks help. Ran through a creature far larger than Doomsday in Thor1, but likely not more powerful. And took on Hulk in Avengers, as well as helping to defeat and destroy and evil robot made of unbreakable metal. Then destroying a dinosaur extinction sized meteor of a landmass with Iron Mans help. So there are his feats.
All in all it comes down to team work. And even though the Trinity had just met. They worked together almost seemlessly. The wjole sequence when Bats hit DD with the kryptonite gas, WW restraining him with her lasso. And Supes delivered the final blow. A beautiful demonstration of team work. No one tripped over anyone or anything.
So all in all I think no prep time or anything the Trinity would be able to pull it off if Magic is out of the equation. Teamwork is pretty much equal. Depends on the line up too. AoU Avengers or Avenger1 Avengers. Cause if its AoU then that includes Quicksilver as well. Quicksilver could be an unfair advantage as well as the only one with Superspeed is Superman.