Lee in the Union

I gotta disagree. The British and French may have made supportive noises, but they had zero appetite to actually intervene in the war. Their own internal politics would not let them openly fight for a slaveocracy baring a major provocation from the Union.

See Blue and Gray Diplomacy: A History of Union and Confederate Foreign Relations by Howard Jones, Chapter Requiem for Napoleon—and Intervention -

Yet Kenner’s secret mission was anything but secret. Reports about it appeared in the Richmond Enquirer and Sentinel in late December 1864. Seward notified the Union embassy in London of the mission on January 10, and the news appeared in the Paris press on March 2. Kenner had left Richmond in disguise on January 18, 1865, lamenting that he would have had a better chance in early 1863, when both England and France were well aware of the Confederacy’s diminishing resources and the battles at Gettysburg and Vicksburg had not yet occurred. “I would have succeeded” in securing a £15 million loan when “slavery was the bone of contention.”​

Now, neither Napoleon nor Palmerston showed interest in the proposal. To Kenner and Mason, the emperor explained that he refused to move without England and that he “had never taken [slavery] into consideration” regarding recognition. On March 14, 1865, Mason met with Palmerston for more than an hour at Cambridge House, where the prime minister also rejected the plan, insisting that slavery was not the obstacle to intervention; the Confederacy had not proven its independence on the battlefield. The Richmond Dispatch glumly noted, “No one would receive us as a gift." The responses should not have surprised the Confederacy. Napoleon’s reply contained nothing different from his initial determination to follow the British lead. Palmerston’s argument against recognition correlated with his long conversation with De Leon in the summer of 1862. On neither side of the English Channel did slavery emerge as the critical consideration.

Uh, no. He also had both Grant and Sherman get their brains blown out in the opening seconds of the battle. I'll grant you that Sherman probably should have been killed in the battle. He was in the thick of the fight from the start and had several horses shot out from under him. But having him killed with almost the very first shot of the battle before he even knows what's going on? Then having Grant similarly killed, when by all reports he never even approached the front lines, commanding from the rear? That snacks of an Ameriscrew. Particularly when none of the Confederates senior officers are killed, despite being at the very front of their men. As an example, in Pickets Charge, 26 of 40 Field Grade officers (Majors, Lt Cols and Colonels) were killed from his division alone. All three of his brigade commanders were casualties with two dieing and one being severely wounded (all general officers). Trimble, a Major General and division commander, lost a leg. So yet more proof that the author set outto deliberately screw the Union and wank the CSA.

And don't forget, the author has the entire force panic, rout, and then get systemically gunned down until none are left. That didn't even happen at Fredericksburg or Gettysburg when both armies marched straight into prepared killing fields. Even at Antietam, which saw over 22,000 killed in a day, neither army was destroyed. So again, the scenario was written as a CSA wank and deliberately screws the Union. Even if everything goes right for the CSA, the battle is not resulting in the outcome described by the author.

I also feel i should remind people of something, since you have now said that "if the original plan had been followed," it would have been a crushing victory. There is a very old military axiom. It states, no plan survives contact with the enemy. Johnston could have followed his plan to the letter, but it would not have gone exactly as planned once battle was joined.

The author does not state Sherman was the first killed, and he has Grant die later in the battle as the Confederate attack develops. Ultimately, however, neither of these detract from the basis of the Confederate victory; a better deployment and a movement that involves not running to the Union Gunboats at Pittsburg Landing. Comparing this to Pickett's Charge ignores the very, very different tactical basis of both engagements. At Pickett's Charge, the Federal defenders were awaiting the attack, which had to come across an open field at them. At Shiloh, however, the Federals were caught completely by surprise and Grant compounded this failure by having ordered his men not to construct entrenchments. In short:

Shiloh: Unprepared Federals caught by surprise with no fortifications
Pickett's Charge: Fortified Federals expecting an attack in the open against them

Further again, you need to consider that comparisons to other battles ignore the changed landscape and orientation of the battlefield. At Fredericksburg, the Confederates were entrenched and allowing the Federals to attack them but, further, the Federals had an open line of retreat. Same goes for Antietam. What the author wrote was Johnston's plan, which was a good one; instead of focusing on Pittsburg Landing, the attack maneuvers the Union forces into such a position that they have no escape due to the prevailing swamps and creeks of the area. If to his rear is flood, impassable swamps and to his front is the Confederate Army, what else can be expected but the total destruction of the force? See what happened to Harper's Ferry in September of 1862, where Jackson destroyed an entire force of 12,000 Federals.

Finally, "No Plan survives Contact with the enemy" isn't meant to be a truism, but to instill a sense of improvisation as the particulars of the battlefield shape up. The vast majority of military operations do proceed as planned; otherwise, how does anybody win wars?