It's known that both Joe Blong and his brother Andrew attended Notre Dame although when exactly they were there is uncertain. According to Notre Dame Baseball Greats, the Blongs were at the university the same time as Michael Brannock and it's known that Brannock was at Notre Dame in 1869.
It's possible then that the Blongs, Dillon, and McSorley were all at Notre Dame at the same time. Certainly, the Blongs were there together and Dillon and McSorley were there at the same time. By 1873, all four were in St. Louis and playing together on the Reds.
The connections between Dillon, McSorley, and Blong is one of the more fascinating parts of the Reds story and I believe is rather relevant when considering the break-up of the team that compeated in the NA in 1875. David Ball has sent me all kinds of information about the Covington Stars and Dillon, McSorley, and Blong's time with the team in the summer of 1875. Hopefully, I can pull that information together soon and post it here at TGOG.