Wow 3 sport athlete's there are so many. You mentioned Hough, Blocker was awesome and so was Jim Brown. There was a 3 sport athlete back in the day named Jeff Carlin he led the County in baseball strikeouts, football touchdowns scored, basketball scoring also in the same year.
Top Nassau football of all time in no specific order would be Hempstead, Lawrence, Freeport, Garden City, Farmingdale. Freeport, Baldwin have played the most games.
Massapequa, Bethpage also very good but not around as long as the above mentioned 5.
Some of these schools played some great competition as well. Schools like Quincy Mass, Brockton Mass, Union Endicott, Rome Free Academy which has the most wins in NYS.
Not sure about the schools you mentioned that played Brockton High School in MA from above? The only school from Nassau (public school) that I know that played Brockton High School was Lawrence in 1922 and lost 57-0. The other Nassau High School that played them was Chaminade in 1996 and lost to them 35-18. St. Johns High School played them in 1986 and actually beat them 8-0.
The school from Long Island that played the most times against Brockton High School was Sachem 1988 (lost 35-7), 1989 (lost 35-20) and in 1990 (lost 42-26)