Frank Frazetta was known by everyone for his fantasy art, but not much attention is given to his humor work. Had he not done the Conan book covers, he might have had the same career as Jack Davis.
I don't think he did the top half
He was almost a regular in MAD but there was a disagreement about keeping the original art.
He claimed not to use photographs for reference, which probably wasn't the case with caricatures. I doubt he could do so many from memory.
I think "smoking" is probably a euphemism here. From PSA in various Warren magazines.