Part of the American Dream is the belief that anyone can step out of the shadows and into the spotlight, given the right combination of talent and breaks. The rags-to-riches possibility lives within everyone despite the daily crises that threaten to squash it.

In popular music, backgrounders sometimes steal rather than step into the spotlight, and record companies - always on the hunt for new stars - immediately sign them to solo contracts. Racks are filled with individual albums from former "supporting vocalists" or "chorum members."

Occasionally, some actually fulfill the Dream. Rita Coolidge graduated from Mad Dogs and Englishmen to Kris Kristofferson to the No. 1 record in the country. Barry Manilow leapfrogged over Bette Midler and became one of the most popular entertainers in show-business history. Yvonne Elliman, Mary Magdalene in the original "Jesus Christ Superstar." who then backed Eric Clapton, is currently on the verge of stardom. Then again, she's been on the verge of stardom for years. This time, however, she's getting a lot of attention via "If I Can't Have You" from "Saturday Night Fever." (Lately, it seems you can have a hit record just by seeing "Saturday Night Fever.")

So the arrival of two new releases heralding performers generally accustomed to the sidelines generates both optimism and skepticism.

Sharon Redd, Ula Hedwig and Charlotte Crossley are "Formerly of the Harlettes" (Columbia JC 35350), which is to say formerly Bette Midler's three backup crazies. They're not just "The Harlettes" for legal reasons (apparently Midler owns that name).

But "Formerly of the Harlettes" offers much more - hints of the Pointer Sisters ("Can't Dance"), Gladys Knight and the Pips ("Ain't No Man Worth It" and "Roll Me Through the Rushes"), Manhattan Transfer and Brasil '77. The trio also packs instrumental wallop from its basic quartet of John Barnes on keyboards, bassist Byron Miller, drummer James Gadson and guitarist Wah Wah Watson. Supplementing them are Willie Weeks, several members of Santana, Sneaky Pete Kleinow (yes, the old Burrito - I didn't believe it, either), and Herbie Hancock, whose electric piano tenderly augments a surprisingly supple vocal reading of his own "Maiden Voyage."

Like many debut albums, "Formerly" tries to touch too many bases and thus sacrifices a more distinct identity. The raw material, though, is quite noticeable.

Patti Austin makes for a slightly different story. For one thing, "Havana Candy" (CTI 7 5006) is her second solo album; she's also a veteran of innumerable CTI dates as a non-featured vocalist. Yet what really separates her from the rest of the pack is that Patti Austin does not want the spotlight.

The reason is simple: As a session singer, she earns a fortune. Why drag yourself out to tour the country for months when you can make the same money in a week in New York City? Why, indeed, except that her first release had the critics tripping over themselves with superlatives, and "Havana Candy" is nearly as good.

Austin's strength is her lyric feel. Compositions like "We're in Love' and "That's Enough For Me" are simultaneously breathless and passionate. Though the production sometimes borders on the overbearing and the material here is not as strong overall as on her first album, Austin proves the equal of such contemporaries as Natalie Cole and Roberta Flack. Besides all that, "Lost in the Stars" is torchy enough to be reminiscent of the old Streisand.

Since she's basically a studio singer, Austin gets help from some top studio musicians, among them Ralph MacDonald, Eric Gale, Richard Tee and Michael Brecker. If she keeps it up, Austin could eventually add a slight twist to the American Dream: She might become a star in spite of herself.