The letter proved nothing except that Lincoln asked Scott to have plans ready for after the change in presidency. Nowhere in that letter is any suggestion or request that Scott not follow Buchanan's instructions or to drag his feet in carrying out his orders. Nowhere is there any attempt to usurp power before his constitutionally mandated date.
Ever notice, rb, that every time you document a point, every time someone makes a good argument, this guy starts hitting the ROFLMAO button?
ROTFLMAO!!!!! That's what you call 'good points'?
Except that Scott did exactly that -- exasperating Buchanan by creating fait accompli regarding the Administration's deliberations over what to do about the forts.
That Scott busted his move at Lincoln's request, given the letter (which indicates previous communication as well) is a no-brainer.
But you're still wriggling, because this shows Lincoln interfering and laying the basis of his war policy.