So when Stanton and Lincoln said they did not want to know Grant's plans, they were lying?
One must remember that Lincoln had continued the process started by Jefferson Davis of undercutting the office of General-in-Chief. He apparently didn't want Grant made GinC, since his people in Congress defeated attempts to tie the Lieutenant-Generalcy to the office in GinC. Grant only became GinC because after Grant was promoted (and simultaneously ordered to the field rather than to take command of the armies), Halleck resigned the office, citing that the Law allowed that the GinC was above all Major-Generals, because the GinC was placed above all officers in the same grade, but there was no mechanism he could see that allowed him to be above Grant. Hence the awkward creation of the Chief-of-Staff to the War Department, a role simultaneously above and below the GinC. Lincoln and Stanton had apparently desired to retain Halleck as GinC.
Nothing had been discussed before Grant departed for Nashville, and when Grant departed, he hadn't been made GinC. Grant had told Sherman that he wouldn't accept the Lieutenant-Generalcy if it meant leaving the west, but he'd gone back on this. His visit was primarily to transfer Grant's old command to Sherman.
Grant returned from Nashville on the 23rd March, and he has a meeting with Lincoln on the evening of the 24th. It is apparently here that Lincoln gives Grant an outline of the plan of campaign for 1864. On the 27th there is a formal meeting at the War Department with Lincoln, Stanton, Halleck and Grant in attendance. It is here that the operational plans are drawn up. Over the next week Grant and Halleck will write the appropriate orders, and make recommendations for changes in command.
There apparently are differences between Lincoln and Grant, which are the subject of the next meeting on 20th April. Grant insists that the 9th Corps should be assigned to him. Lincoln wants the planned desant against Wilmington to go ahead. We know that Grant gets Lincoln to agree to the 9th Corps moving forward, citing a potential threat of Longstreet ascending the Shenandoah to move them to Manassas Junction; hence as soon as battle was joined in the Wilderness, an order to Burnside from Grant brought him south of the river.
However, the plan is essentially Lincoln's. Simultaneous advances on all front was something Lincoln had been advocating for several years (and something taken from McClellan's planning). A direct advance against Lee was what Lincoln had been advocating for the same period. Very little, if any, of Grant's ideas made it into the plans. However, after the Wilderness Grant turns away from Lee and tries to march south to the James, as he'd told Butler he would.
You, of course, are referring to Lincoln's 30th April communication. Whilst Lincoln states he doesn't know "the particulars" of Grant planned movement (and indeed Grant didn't yet know - he is still vacillating), it is clear he knows the general plan. Indeed, it is Lincoln who is the primary author of it.
You claim "Stanton and Lincoln said they did not want to know Grant's plans, they were lying?", and the answer is, you are misremembering. They did know Grant's plans, and their knowing was a prerequisite of Grant being allowed to act.