There's a quarter of a million Italians in the Metro Detroit area, more if you count the Windsor suburbs. I personally know a lot of families in the area who are newer arrivals, (last 15-20 years or so). I think the term "zips" is an overreaching term in this context. I think it means more of the Italian born guys who have been here for many years, vs a new transplant. But I personally believe there are those guys as well. You have to remember the D'Anna family controls Terrasini in Sicily to this day. And Terrasini is where most of the historical Detroit families are from. Food for thought.
Another thing to consider is the Detroit-Windsor border is the busiest border crossing in America, in terms of traffic and monetary movement. It's funny you mention Montreal, because it's been reported that Canadian mafioso have increasingly been using the Detroit-Windsor crossing in smuggling. That requires man power and cooperation between existing mafia families. Am I insisting the Detroit family is moving weight like Montreal? Absolutely not, but there is more than likely a working relationship between the Detroit "zips" and the Canadians. I've also heard there is a crew from one of the families from Toronto in Windsor for this exact reason.
Are your family members in the Detroit area Kuci?