Just because the deal is signed doesnt mean its complete. You cant proceed with the deal unless all parties have signed a binding agreement. Using your house analogy its like it has contingencies, in this case instead of an appraisal its the approval of the PL. While we dont know what it is I find it highly unlikely there are any clauses that let 777 just consider whether they still feel like they want to buy it. The PL likely doesnt waste its time and money reviewing paperwork for those that might someday own a club.
The binding agreement in your scenario is the "deal."
If you buy a house you sign a contract, contingent on meeting criteria (funding, inspections, etc).
If I no longer want to buy the house, I forfeit my deposit and that is the penalty for doing so.
When you sign a LOI to buy a company, it is contingent as well (funding is the largest).
If 777 can't close the deal for whatever reason, there are likely contingencies (or penalties) around that.
On the club's side, there are likely provisions as well in terms of good faith provisions so they can't kill the deal if the get a better offer etc.
Those all likely have time limits.
But the deal is not complete, you can't force 777 to buy something they can't or no longer wish to.