At the time, I wondered if the German baron story was correct, and if a member of the Jaeger family hadn't built it instead. That's because an 1896 map showed that A.C. Jaeger owned the land, and the road on which the house sat was once known as Jaeger Road.
Ah, but as usual, I should have done a wee bit more research.
Thank goodness that after I posted Part 2, emails from several local historians and history buffs started pouring in. I received valuable help from Renee Dore, Rick Kurish and longtime contributor Jeremy Reynolds that enabled me to do this follow-up post.
It turns out that the man who built the house was indeed "an exile from Germany" as stated in the Journal article. His name was Ludwig von Baumbach.
According to an 1897 collection of biographical sketches of Wisconsin business leaders published by the Evening Wisconsin Company, Ludwig von Baumbach "was of aristocratic origin, the family being landed proprietors, which in the old country means more as to social position than it does in this. He entered the army and rose to the rank of captain. Leaving the army he took part in the political agitations of the times, was elected to parliament and joined the liberal element in its effort to secure the establishment of constitutional government. As every one knows who is familiar with the history of those times, the effort failed disastrously, the government was more strongly established than ever, and those who were outspoken in their advocacy of the revolution were compelled, as a measure of personal safety, to leave the country. Ludwig von Baumbach was one of these. He came to this country and settled on a farm at Black River, Ohio, but, subsequently, in 1857, removed to Milwaukee, where he lived the remainder of his life, dying in 1883. Not long after coming to Milwaukee he was appointed imperial consul to Germany, which position he held until 1878."
(Here's the link to the website containing this information, as well as that of one of Ludwig's sons, Charles, who was a successful druggist in Milwaukee.)
An 1857 Black River Township map does indeed show Ludwig von Baumbach's name and residence on the property next to Beaver Creek that overlooks the golf course today.
Anyway, it's nice to get the early history straight on that house once and for all.
Special thanks to Renee Dore, Rick Kurish and Jeremy Reynolds for their help with this story.
****UPDATE (December 2019)
Here's a December 2019 view of the house.