Assuming everything is void, I would have very little doubt that Leeds & WBA would be fighting their case, I would suspect SUFC & MUFC would consider their options & i can guarantee you multiple clubs (probably collectively) would be taking legal action if they were forced to return TV money (circa $200m per club). Can you imagine Sullivan, Gold and co just handing back that kinda money and saying "fair enough"
This is a global crisis and frankly, football is utterly irrelevant in the grand scheme of things, but when this eventually passes, no matter much damage is done, the same grubby, self motivated greed will sadly prevail after in football & that's why despite the moral shame, I am sure the legal route will be taken by some, if not many. All we can hope is the society in general changes, but shame is not something to stop football club owners.
Perhaps CAS or someone similar might be able to pre-empt the legal challenges with some sort of "all decisions to restart football" are final.