Not all Lutherans up there are Scandinavian. Many are German, including both sides of my family. Seems most Catholic Germans are down here in MD and thereabouts - Bavarian types (also part of my mom’s family).
The old stereotype is that rural MN was split between Catholic Germans and Norwegian Lutherans and that the two groups were always fighting for control. But I’m sure that many German Protestants (including Lutherans) also emigrated to MN after the 1848 Revolution (even though Catholics from Bavaria appear to have been the most numerous German immigrants during that era).
Living all my life in Minnesota - I always heard that the population was about 22% Catholic and 24% Lutheran. Of course, the demographics are changing with mobility, and the surge in non-denominational Christians in the past 20-30 years.
Re: German Catholics in Minnesota (and in Wisconsin), they settled in pockets, primarily in the eastern and central part of Minnesota and all over Wisconsin.
In central Minnesota, the major group of German-speaking Catholics were the Rheinlanders and the Luxembourgers intermixed with folks from Westphalia, Oldenburg, Baden and Bavaria. Stearns county also has the first settlement of Slovenians in the USA - St. Stephen. They were Catholics from the Austo-Hungarian empire and spoke both German and their native Slovenian dialect.