I never saw Liddell. The other 5 were absolutely different types off footballer but in the old sense of a left winger Heighway was the purest definition of such, hurting down the line at warp speed, beating players with sheer pace and magical crossing skils.
Barnes was a left winger too, more skilful than Heighway but I don't recognise any others of your list as definitive left wingers.
As effective footballers I'd say Heighway, Barnes and Mane and wouldn't argue with which order they are in. But Heighway is always overlooked, as is Keegan, and I remember how utterly, devastatingly brilliant they were.