I have not heard the story that Wilhelm was a minister. It does not seem likely based on his occupation when he emigrated and the fact he lived his life on his farm (per the census records).
My branch of the family continued to use the spelling "Hell" at least in the church records I looked at. I do not know about the other two sons. The youngest child I show is Wilhelm Leberecht Paul Hell b. 11 Jul 1858, maybe he became a minister.
The land patent that says Milwaukee only means he was living in Milwaukee when he purchased the property. The legal description of the land is Township 9 Range 21 which is located in Washington County (now Ozaukee County - Ozaukee County was part of Washington County until 1853 when it was formed into a new county). In fact, the 2 parcels of land are next to each other. Thus, he had a farm of 120 arces (he owned 3/4 of section 7). The dates on the land patents are not purchase dates, they are the date when the federal government issued the patent. When one purchased land from the government (his land cost him $1.25/acre), the federal government issued the owner a "Land Patent" to confirm the land purchase. Land patents were issued anywhere from 6 months to 3 years after the land was actually purchased.
I have attached a scan of the inside cover of an old book by Luther, does your book look like this one? It is also part of a series of 7 (I believe). I am aware that Pastor Kluegel owned at least 2 of these books. Are there any names written in the book?
In the 1840s, some of the settlers in the Freistadt area did not like Pastor Krause (for a variety of different reasons) and never joined his congregation or dropped away after they got to know him. There was a preaching station on Mary Buth Road (about 2 miles away) that was served first by Pastor Kluegel then by Pastor Pankow. If Wilhelm did not join Pastor Krause's congregation they might have attended at the preaching station.
Pastor Krause left Freistadt in 1848, after his congregation split into 2 factions. One faction remained loyal to the Buffalo Synod and the other, larger, group joined the Missouri Synod. From 1847 until about 1868 there were 2 Lutheran churches in Freistadt (right across the street from each other). Around that time, the majority of the congregants of the Buffalo Synod church joined the Missouri Synod congregation. The remaining Buffalo Synod congregation was to small to continue so the Buffalo Synod church disbanned.
My branch of the W&S tree lived in Cedarburg Township, Ozaukee county after they married in 1869. They moved to the Kichhayn area and then to Milwaukee. They were members of Buffalo Synod churches after they married and until they died.
If you need anymore details, feel free to ask.