Fill a large pot with a few inches of water and put a steamer basket inside.
Put the corn in the bottom of the steamer basket and put the lobster tails on top. Close the pot with a tight-fitting lid, then put over medium heat and bring to a simmer. Steam until the lobster tails turn red, about 7 to 8 minutes. Remove along with the corn and set aside to cool slightly.
Once cool enough to handle, remove the lobster meat from the shells and cut meat into 1-inch pieces.
Cut the corn off the cob and place in a large bowl. Meanwhile, preheat the oven to 425°F.
In a medium bowl, add the cubed rolls, salt, pepper, and butter. Toss to coat, then transfer the rolls onto a sheet tray, spreading into an even layer.
Toast in the oven until golden-brown, about 7 minutes. Remove and set aside to cool.
In a large bowl, add lobster meat and juices, toasted croutons, parsley, celery, scallions, and basil.
In a different medium-sized mixing bowl, add the lemon zest, mayo, lemon juice, tarragon, and salt and pepper.
Whisk to mix, then transfer the mixture to a squeeze bottle. Pour half the dressing over the lobster mixture then toss. Fold in the corn, but try not to break up the kernels.
Add a small amount of the mayonnaise mixture to the bibb lettuce. Make a bed with the dressed bibb lettuce and serve the lobster salad and croutons on top.
