If you want to include a similar phrase in your reply email just for fun, you can use the following Latin phrase:
ab ovo usque ad mala
It's basically the same thing as soup-to-nuts, except that it literally translates to "from the egg to the apples". This was the typical main meal in ancient Rome, where the phrase was created.
Meaning
Etymonline.com says of handy:
Meaning "conveniently accessible" is from 1640s.
To come in handy means something will be handy or useful in the near future, that it will become handy.
Come in handy
The earliest verifiable examples I found in Google Books are both from 1843.
First, in a "Weekly Journal of Gardening" column of The Gardener and Practical Florist:
CELERY, as we always recommend in small gardens, should be planted out at various seasons, and if there be any left in the seed bed, another row will come in handy. Earth up that which is advancing. LETTUCES in the seed bed may be thinned, and those taken out may be planted.
July 15, 1843.
Second, in Tales of the Colonies, or, The Adventures of an Emigrant, Volume 2:
"What have we got here ? a pair of handcuffs ; ah ! these come in handy ; the bushranger won't want handcuffs any more, but they'll do for his mate."
Come handy
We can also find some slightly early uses of the similar to come handy. It was once used similarly and as often to come in handy, but lately has become rarer.
An October 1824 The London Magazine prints a letter from summer 1821:
please your oner,
hoping your oner wont be displeasd at my boldness and I send a little basket of eggs-good fresh eggs-and they were lade by the little black hen that's three yeer ould come Michaelmas eve the day that I send home your oner's shute— and the times are very hard intirely — intirely — plase
your oner from
your oner's sarvent to comand,
Timotheus Kinnealy.
the woman hopes the eggs wil come handy to the young mistris out of her confinement. — tuseday mornin.
Best Answer
'From soup to nuts' in reference books
Christine Ammer, The American Heritage Dictionary of Idioms (1997) has this entry for "from soup to nuts":
Judith Siefring, Oxford Dictionary of Idioms, second edition (2004) says that the "soup to nuts" form of the expression originated in North America:
The Cambridge International Dictionary of Idioms (1998) agrees with Siefring in concluding that the expression is "American, informal."
Early instances of the phrase in Google Books search results
The earliest Google Books match is from William Hall, The Turnover Club: Tales Told at Meetings of the Turnover Club, About Actors and Actresses (Chicago, 1890):
The first unmistakably figurative use of the phrase is from an advertisement in Men's Wear semi-monthly (1909) [date not confirmed, combined snippets]:
Three additional instances appear in 1911, and the idiom by then seems to have been well established.
Early instances of the phrase in newspaper archives
A search of the Library of Congress newspaper database pushes the earliest occurrence of "from soup to nuts": to the 1880—and it may already be a metaphorical use of the phrase. Here are some early examples. From "John McDonald: The Hero of the Whisky Ring Promises a Startling Sensation: from The Chicago Times, reprinted in The Sedalia [Missouri] Weekly Bazoo (May 18, 1880):
From "The Close of Stewart's," in Frank Leslie's Sunday Magazine, reprinted in The [Canton, Ohio] Stark County Democrat (May 18, 1882):
From "White House Feasts," in The Chicago Times, reprinted in The [Austin, Texas] Weekly Democratic Statesman (February 1, 1883):
And from "A Boy's Essay on Julius Caesar," in The [Salem, Oregon] Evening Capital Journal (September 28, 1888):
Conclusions
The expression "from soup to nuts" was in use in the United States from at least 1880 forward. Very early instances either referred to actual fancy formal dinners or metaphorical ones. But by 1888 people were beginning to use the phrase independently of the context of real or imagined feasting.