All of the people you mention in the 3rd paragraph are relatives of mine. Johann Peter Paar (married to Christina) was the brother of Peter John Paar (Margaretha). They were the brothers of my gggrandfather, Peter Paar, who was the oldest and did not come over from Prussia.Caroline Paar was the wife of a 4th brother, Johann Daniel Paar.
I haven't been able to link any of the Marcus' that I've come across over the years.Do you have any details (DOB, etc.) concerning the Peter you mention?
In another posting you did on another site, there was talk of the Paars in Ohio.To my knowledge, none of my relatives emmigrated to Ohio.