Barely? What are you talking about? You said it yourself, Hulk on his own has done it. How are they suppose to beat him and Thor, a much bigger threat than the Hulk (because of his versatility.) Iron Man has an incredibally diverse arsenal. Cap may not be able to Hurt Reed but he could probably find a way to take out Hulk and Human torch, not to mention that he would rally this team to a 15 second victory (and i'm being generous.)
I mean, you heard yourself right? "Hulk has taken on the entire FF team before with excellent results"- USAgent. And that somehow means that they magically have a chance against these four?