Just moved from Texas to the mountains of Colorado, so not as cold as you are gonna get in WI but close as I live above 9k feet (temps are similar but, don't get the windchill and it's more sunny here)

First thing that comes to mind is a good anorak & Flannel or Wool shirts to deal with the winters.

I just ordered a Anorak for my wife, so was doing a bit a research and the two I would tell you to look at would be:

"Cheaper Option"

https://www.borealmountainanoraks.com/

Expensive Option

https://weatherwool.com/products/als-anorak

(neither one is "cheap" but you get what you pay for)

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I ended up going with the expensive option, mainly because of the breathability of WeatherWool's anorak, my wife and I both run hot so anything that doesn't breath very well is going to limit us to wearing it only when it's very very cold. If you run cold, the boreal would probably be better as the only criticism that I read for that one is that it run hots as that wool isn't as breathable.

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Next up is flannel or wool shirts

LL Bean or Eddie Bauer is the easy way to go here. There are better options (Duckworth), but in the beginning you need to be able to buy a couple and can focus on upgrading over the years.

Lastly, the number on thing I will tell you. Is to start looking at more wool products in general (especially if your an outdoors can of family), and the reason for this is that wool retains heating properties when it's wet and you are moving to a very cold and wet environment. There are youtube videos of people putting on the wool anorak's and then jumping into freezing water and getting out and just sitting there and able to stay warm and not get hypothermic.