The reason I asked is because nobody seems to have put a lot of analysis into the federal operational planning side of the fall/winter campaigns of 1862. Your article is focused on Van Dorn, so I can see why you wouldn't delve into the federal side of things as much. But I really think Grant's overland campaign of 1862 had already been terminated by Lincoln and Halleck, who envisioned capturing Vicksburg via an exclusively riverine campaign and had told Grant "go no farther." Grant's plans to meet up with Sherman were wholly contingent on Sherman's success at Chickasaw Bayou. Given that Sherman's expedition (which was Halleck's idea, not Grant's) was doomed to failure, the great irony of Van Dorn's raid seems to be that it expedited the movement that eventually doomed Vicksburg: Grant moving to Milliken's Bend to take command of the "Army of the Mississippi" in person.
I also think more is made of the effect that Van Dorn's raid had on Sherman's Chickasaw Bayou expedition than is warranted. If you track what Pemberton knew and when, the detachment of Gregg's Brigade and Vaughn's Brigade took place before Pemberton knew that Grant was moving back to Memphis. These were the only two units to participate in the Battle of Chickasaw Bayou. Gregg's Brigade mostly sat in reserve, and Vaughn's smallish conscript brigade guarded an unfordable section of McNutt Lake.