who are their rivals in the first one?
Blair Academy
Peddie School
Peddie's arch-rival is Blair Academy, and the two schools compete every year during the second week of November for the Potter-Kelley Cup. 
who is  finn m. w. caspersen? American financier and philanthropist. where did he study? Peddie School, Brown University, and Harvard Law School. which all sports were entertained in the first one ? Football, Basketball, Tennis, swimming, etc.
wiki:20701761
Peddie School [SEP] Football rivalry
Peddie's arch-rival is Blair Academy, and the two schools compete every year during the second week of November for the Potter-Kelley Cup. The day of the football competition, which alternates yearly between campuses, is known as "Blair Day" at Peddie (and "Peddie Day" at Blair). The game between the two schools is the oldest football rivalry in New Jersey and ranks among the oldest in the country.