My definition of "sound" means that with best play by both sides--it does not lose. My guess is the Smith Morra and Albin Counter Gambit and Sicilian Wing Gambit are all "unsound"
I have played the Smith Morra enough that many of my games were published by Ken Smith.
Smith Morra is sound because it gives enough compensation for the pawn but no more. Sicilian Wing Gambit is unsound. The Albin Counter Gambit is not unsound but it should leave white with an edge. It does provide sufficient counter chances for black. Therefore it may be considered sound for practical purposes at ratings of below 2300, say, which is most of us.