Early 'how's about'
The earliest instance of the expression, in any form, that I could find in Google Books and Elephind newspaper database search results is from Bob Russak, "The Art of Plugging," in the New York Clipper (December 19, 1914):
Yes, I agree with you, I'm getting old, but I still will give any of those young fellows a run for their money. I can't possibly forget the first day I was sent out for an act. I was at that time with the Consolidated Music Co., at 10 Union Square, when Seymour Furth was manager. The boys were of an opinion that I wouldn't make good, and said, "here's a fellow that wouldn't last long, how's about playing a joke on him?
The Clipper was not a regular daily or weekly newspaper; rather, it was a weekly that billed itself as "The Oldest American Theatrical Journal."
The next Elephind match is considerably later and appears in an editorial headline of a newspaper far from New York City. From "How's About Weihaiwei," in the [Honolulu, Hawaii] Daily Nippu Jiji (June 5, 1923):
How's About Weihaiwei
It was in December, 1922, that Japan, conforming to the agreement she entered into at the Washington conference, retroceded to China the port of Tsingtao which she acquired as a natural outcome of the World War, and completely withdrew her troops from the province of Shantung.
Six months have elapsed since the retrocession was effected, but Great Britain which, like Japan, promised China at the Washington conference that she, too, would give up Weihaiwei, is mighty slow in carrying out hr promise. How is it with Weihaiwei? This is the question which is being asked here and there.
There is enough of an echo of the editorial headline "How's About Weihaiwei" in the subsequent question "How is it with Weihaiwei?" to suggest that the editorial writer sees "How's" in the headline as a contraction of "How is it," with a meaning along the lines of "What's going on." It is rather more difficult to draw the same conclusion about the usage of "how's about" in the New York Clipper article from 1914, however.
And then, from "Hawaii's Young People in Old Capital Go Mushroom Hunting," in the [Honolulu, Hawaii] Daily Nippu Jiji (November 9, 1927):
Forty minutes' ride brought us to our destination [Ishiyama, Japan]. We then visited the Ishiyama Temple and other places of interest. On our way back we ate Chikara-mochi (strength-cake), made in honor of Benkei, a historical knight. We all agreed that this cake gave us strength for we walked a distance of two miles for the depot without getting tired at all after the hard hunt [for mushrooms]. ...
...While we were walking fast to the station we saw an old woman in distress. She was trying to pull her cart out of a hole in the road. The cart was heavily loaded and the hole was quite big so the work was too much of this poor woman. She pulled and pulled but without success. We came along and the girls went to the rescue of the poor woman. The cart was pulled out. It was again agreed that without the aid of the Chikara-mochi it would have been, impossible to help her. Say, friends, how’s about making this mochi in Hawaii.
Then back to New York, in a Hathi Trust search that yields this entry in Library of Congress Copyright Office, Catalogue of Copyright Entries, Part 1, Group 3 Dramatic Compositions [and] Motion Pictures, volume 1, number 1 (1928):
How’s about the pents? a play in 1 act, by L. Kornblueth. (C) 1 c. Oct. 17, 1928; D 86509; Leo Kornblueth, 243 Hart St., Brooklyn, N. Y. 4982
From Ted Sokol, "Personal Piffles" in the [Cleveland, Ohio] Case Tech (January 14, 1932):
Hey, guys, whatsa about it all? Huh? Whatsa about all these smoothy instructors who stick around school a year or so and all of a sudden find out that two can starve almost as good as one? Howsabout it?
From an unidentified article in Motion Picture, volume 47 (1934):
What everyone is wondering is: Will they keep that famous dance on the long staircase in that new version of "The Merry Widow"? It is well-known that as a dancer, Maurice is a good singer.
From J.R. Allen, "Loco Weeds," in the [Cleveland, Ohio] Case Tech (April 21, 1932):
Was de yunkest son bonded hup to hees fodder, say, "Howzabout me chuppink from de furrest, puppah? I'll may not be a beeg tuffie like Zeke and Ferdy, but we'll gonna heffta hev de keendling wood for de keendling de stove."
From an unidentified item in The Film Daily Year Book of Motion Pictures (1935):
If you were up on your geography, you'd know the popular remark was making the rounds before he extended his executive attentions from the RCA fold over into RKO and became the toughest guy for film trade-paper reporters to see. So, this being the amenable season of the year, howzabout giving him the benefit of the doubt, that he's the type of exec who prefers doing to talking, and for further data see the recent results of Radio Pictures, of which he is president.
And from an untitled item in the [Bloomington, Indiana] Bored Walk (February 1936) [combined snippets]:
"Let's eat, dring, and be merry! I like the Creole babies—they're the best neck. Howzabout it?"
"I don't know—I've never eaten any."
Early 'hows about'
The earliest Elephind match for the spelling "hows about" (with no hyphen) is from Aunt Haru, "Pins! Pins! Pins!" in the [San Francisco, California] Shin Sekai Nichi Nichi Shinbun (September 23, 1933):
We have reservation for 41 pins already, but we must have 50 in order to place an order, so come on you members who haven't alt ready made reservations, hows about it?
But just two weeks later the same newspaper uses the spelling "how's about." From "The Club Hamanoya....: Intimate Impressions of Lil Tokyo Night Club," in the [San Francisco, California] Shin Sekai Nichi Nichi Shinbun (October 6, 1933):
"Are there any attractive girls in Northern California?" she ["Madame Tokio," the club's manager] asked this one particular evening of your correspondents. Let me know if there are any—" (How’s about it, girls?)
A publicity agent also informed that special service, and attention will be given to nisei member to specify that—and tell your friends. Goodbye." Bye! be seein' you again."
Early 'howz about'
From "Rummagings," in the [Santa Rosa, California] Oak Leaf (September 22, 1933):
The next time they have a convention in town they ought to fill the swimming pool with grog—furnish every individual with a tin cup (smoked glasses not necessary) fence in the place and let nature take its course . . . Champagne from a tin cup. Howz about it???
From "Arithmetic," in International Stereotypers' and Electrotypers' Union Journal (1934) [combined snippets):
"Mex, darlink," purred the plump Mrs. Zuckerman, "today is guess vot?"
"Dun't bodder me," replied Max.
"You silleh lettle boy," she persisted, "twenteh-fife years today ve are to-gedder! Howz about a hog, a skviz vit some kisses?"
"No!" yelled Max, "go jomp from a vinder!"
"Mex! how could you tritt me like diss?"
"Because," was the reply, "ven I tink how if I had you bomped off on de foist day—de most I could get vould be fifteen years—and for ten years already I vould be single."
From Bill Van Dusen, "Sidelights from the Sidelines," in the [Santa Monica, California] Corsair (January 9, 1935):
Although the support hasn't been poor, it hasn't been what it might have been.
In order to have league-topping teams the student body must be behind them.
How'sabout a basketball crown this year.
The earliest form of "how's about" that I could find is the one with the apostrophe in place and the word rendered as two words. The earliest instance (by a fairly wide margin) is from a New York thetrical paper in 1914; then come instances from Hawaii in 1923 and 1927, and then another New York instance from 1928. Alternative spellings begin to appear in 1932—the year when the expression seems to break out of its localized popularity and spread across the United States.
It would be hard to identify two U.S. locales significantly more distant from each other than New York City and Honolulu, and I consider it somewhat more likely that the expression arose independently in the two places than that a New Yorker carried it across the cintinent and half th Pacific Ocean to Hawaii, where it took root like an invasive species. But that is a possibility.
What the two locales had in common in the first quarter of the twentieth century was a high percentage of non-native English speakers. It is thus possible that "how's about" emerged in both place by analogy to other English expressions. For instance, Elephind returns matches for "How's tricks" from as early as 1873.
Another expression that seems syntactically tangled in a somewhat similar way is "how's by you?" Leo Rosten, Hooray for Yiddish (1982) claims that this expression originated as "Yinglish" (his word for a hybrid of English and Yiddish"), but the earliest instance of it in a Google Books earch is from 1928, so it doesn't have a good chronologial claim to be an inspiration for "how's about."
But whether adding a "z" sound to "how about" is a natural thing for some non-native English speakers to do to make the phrase easier for them to say is a separate issue from the question of why a writer, seeking to represent the sound of "howzabout" on paper would resort to adding a hyphen to "hows." The answer in that case may simply be that doing so makes the speling look more normal, even though the "how's" in "how's about" doesn't have any obvious logical connection to "how is" or "how was" or "how does."