Well to be fair, I think Kidd could beat them all save Enel.
It doesn't take much to take out Crocodile, just a water trick. Anyone could do that I believe, it's just a matter of executing the attacks would be different. Though yes, Luffy's rubber properties could make a difference in a lot of fights, especially when we are talking about endurance.
For the other guys (save Enel), Luffy beat them all with brute force. I think Kidd can do it too, given the fact of the protagonist laws be applied xD Not so much being dictated by the fruit's power, although it does acts as a catalyst and method to execute the attacks.
Enel is a bad combination for Kidd honestly >.>; I still regard Enel as having the second most powerful fruit ability (everything else discounted) after Blackbeard so far. And with his lightning vs metals (that Kidd's magnetic power attracts), doesn't take a genius to tell what would happen >.>;; Someone is getting electrocuted >.>; Kidd without magnet, he'll be dead too.