[richardfontana]

I'm not sure I've ever heard anyone use "youse guys", but "youse" without "guys" is indeed a now-archaic New Yorkism. However, it doesn't have any particular connection to Italian-American New York other than the fact that "youse" was a native New York dialect formulation that US-born children of Italian immigrants, along with many other ethnic groups, adopted naturally. I understand that "youse" is prevalent in a number of dialects in Ireland and England and presumably spread to New York City through earlier waves of immigration from those places, assuming it wasn't independently re-invented. If I am remembering correctly, "youse" or "yiz" is used in dialogue in Stephen Crane's Maggie: A Girl of the Streets (https://en.wikipedia.org/wiki/Maggie:_A_Girl_of_the_Streets) which depicts late-19th-century Irish-American New York characters.

My sense (as a native New York person who grew up around an older generation many of whom naturally used "youse") is that use of "youse" may have been somewhat correlated with being a member of a European-descent pre-WW2-immigration-origin Catholic-identifying ethnic group (so, in particular, Irish, Italian, German), but I'm not even sure that's so.

By the time I was growing up, "youse" was a class and (maybe secondarily) ethnic marker, largely rejected by the Baby Boomers and later generations in favor of the more nationally standard "you guys". If the seemingly redundant "youse guys" occurs at all it must be an odd conglomeration of the older and newer usage.

[shagie]

Linked in another comment... The Dictionary of Regional American English https://www.daredictionary.com/search?q=yous&searchBtn=

[TRiG_Ireland]

Being in the midlands of Ireland, I say ye; but I believe that yous is more of a think in Dublin and the north.

(In practise, I write ye more than I say it, I think.)

[madcaptenor]

My native dialect is Italian-American South Philly, and "youse" occurs there too, although it may have literally died out by now.

[zdragnar]

"yous" (slightly different s sound) is also common among the rural older generations in German and Dutch immigrant areas. My grandma used it all the time, though not with the double plural "youse guys", just "yous"

[bitwize]

My grandmother fit that ethnic profile, and used "yous" as well.