The Germans always had the impression the Americans were weak and would throw in the towel if punched in the nose.
Hitler should have thrown everything at the Soviets.
I don’t think so. I don’t think the offensive would have had much of impact on the Eastern Front, as the Soviets had such overwhelming superiority by then.
The Germans did correctly pick the right area to attack, the Ardennes Forest was the most lightly defended area on the Western Front.
I think the offensive could have succeeded if the Germans had adequate air support and fuel supplies.
Since they did not, it was simply a waste of scarce resources.