Trinity Lutheran church is not the "mother" church of St. John's. The two churches had a working relationaship in the first few years when Rev. Dulitz was the pastor, but that was their only connection.
Trinity Lutheran church was formed in 1847 when part of Pastor Krause congregation (his congregation included Freistadt and Milwaukee at the time) left and joined the Missouri Synod. They were previously affiliated with the Buffalo Synod.
Also in 1847, a separate group of more liberal Lutherans had been meeting in the Zuehlsdorf home on Sundays and invited Rev. Dulitz to preach to them. Pastor Dulitz had only recently arrived in Milwaukee and was also preaching at Salem Lutheran church (he preached there for about six months). In 1848, St. John's formally issued a call to Rev. Dulitz. He accepted and was the pastor at St. John's from 1847 to 1856.
The group that called Rev. Dulitz included the names: Wilhelm Schroeder, Philipp Hamm, Heinrich Kiewit, Johann Bensemann, Friedrich Boese, Georg and Friedrich Kuetemeyer, Lindenschmidt, Westermann, Friedrich Poehlmann and Heinrich Steinmann.
Pastor Dulitz was unaffiliated with any synod at the time and so was St. John's. Sometime in the early to mid 1850s, Pastor Dulitz recommended that St. John's merge with Trinity. This caused a big rift at St. John's and Pastor Dulitz was forced to resign.
I believe (but am not certain) that St. John's joined the Wisconsin Synod for a period of time but has since left that organization and is once again an unaffiliated Lutheran church.
I live out of state and wrote to Pastor Hastings a few years ago. He was very helpful and sent me copies of all the items I requested (copies of the original church book - in German). I did send a contribution to his church.