Firing on Sumter wasn’t a sneak attack.
Lincoln was well aware of the previous attack on the Star of the West and knew he was provoking a similar response.
"Sneak attack" makes no difference.
What matters is that it was a direct military assault, not accidental, not unintentional and not by disorganized militia.
It had a military commanders, a military objective and was fought on military terms.
The only difference I would acknowledge, but you would certainly deny, is that Pearl Harbor was "state on state" military while Fort Sumter was "rebellion" or "insurrection".
Indeed, if you ask the question, "why in the world would the Confederacy go to the trouble of formally declaring war on the United States?", May 6, 1861, one answer is to gain recognition that they were, indeed, a "state" not just some insignificant rebellion.
So, if for these purposes we acknowledge the Confederacy's "statehood", then Fort Sumter was, like Pearl Harbor, a "state on state" military assault, and each began the greatest wars in American history.