Can you tell me if Laurel and Hardy, Abbott and Costello, and Martin and Lewis were essentially gay acts? Anon.
Are you asking if these guys were gay, or if they engaged in gay humor? On the burlesque circuit many decades ago, along with comics and show girls, there was a type of material known as "nance" material (possibly short for "nancy boy," British pejorative slang for homosexual.) When comics did nance material, it meant they acted like stereotypical homosexuals, made fun of them, for laughs. I don't know if Laurel and Hardy or Abbott and Costello ever indulged in such humor, but Martin and Lewis, especially Lewis, certainly did in the early days. (Such material was considered unspeakably vulgar by many, and certainly not fit for children. When some vaudeville and burlesque comics made it to radio, Hollywood, or television, they had to clean up their acts, and nance material had to go.)
As for the private lives of the six gentlemen you mention -- Stan Laurel, Oliver Hardy, Bud Abbott, Lou Costello, Dean Martin and Jerry Lewis -- I have never even heard any rumors about any of them. Jerry Lewis has made no secret of the fact that he certainly loved Dean Martin in the platonic sense. In their early films it often seemed as if Lewis' character had a "crush" on Martin, but this was acting. In a more innocent and naive era, Laurel and Hardy were often shown sleeping in the same bed together (this rarely if ever happened with the other two comedy teams, who came later), but this wasn't meant to infer a sexual relationship between the two, although they may well have seemed like a pair of bungling gay lovers in some of their movies. Laurel frequently dressed up in drag (transvestism, not homosexuality) but this was done simply because he looked hilarious. There have been numerous biographies about these gentlemen, both in pairs and as individuals. If any of these guys had any gay relationships, they were certainly discreet.
Laurel and Hardy did one silent short in which they kept trying to change their trousers in an alleyway, but were always interrupted by people who presumably thought they were walking into the middle of a homosexual tryst. At least I've heard that's what it seems like. Whether or not this was the intention of the filmmakers -- or of Laurel and Hardy -- has been lost to history.
But, no, I wouldn't say that any of these famous comedy teams were "gay" acts.