I think the only way it makes sense is if it is purely about revenge. Someone is out to hurt the whole family, one member at a time.
So Zach wasn't blackmailed to keep playing football; football was the leverage to force him to make Will unhappy. After he told Will, they took football away. So, now he can have Will but loses football (with his whole prior record discredited) and, once they figure out it was all about Will, it'll probably destroy their relationship anyway.
JJ loses a relationship and a career. The rest is collateral damage.
Now I'm wondering again about Marc. Whoever is behind this is playing a long game and Marc always did seem a bit too good to be true. Is Marc another pawn in the game, the one who alienates Brad from the family and distracts him from his business long enough for someone to destroy it?