***So, which church did Alexander Campbell found?***
To begin with, the Brush Run Church in Pennsylvania, and if it were not for the the Campbells and Stone, the Churches of Christ or the Disciples of Christ and all their splinters would not exist.
The Campbells left the Presbyterians and adopted some Baptist thinking before they went headlong into the Restorationist movement, which acted to jettison all liturgical theology and towards a personal theology created from whichever Scripture that one happened to read that day.
The more conservative Churches of Christ will often refer to themselves as Campbellian (versus the Stone Disciples of Christ churches).
So, that is the denomination you believe he started?
I haven't heard of that. If helping start one private church makes someone guilty of starting a church, then you must believe hundreds of thousands of people are guilty of such blasphemy.