From what I understand, both encourage parties to mediate vs court cases. 

A buyer will not be happy to lose it and since its in an escrow account, you can't receive it until both sides agree or until you fight about it through mediation or a court process.

Your contract will state the remedies…often, mediation is required before court action.  

Then out to mediation.

You could approach planning and have them mediate a solution by having everyone involved register the appropriate encroachments.

That means your home stays damaged until a resolution is reached in court/mediation. 

Plus most MLS purchase contracts have mandatory mediation in them anyway so those who jump right to get an attorney are not really giving real world advice its just knee jerk reaction like and attorney can fix these small simple squabbles.   

From research, it sounds like this needs to go to mediation now- How does this work?

I've had a decent amount of experience in Philly landlord-tenant court as a volunteer mediator during law school. 

That means you have to pay your attorney $75,000 to $100,00 just to get to your first mediation ordered by the court and you still have to pay at least $50,000 to $150,000 for what I call 'Go Away Money' to make the case go away so you don't have to go to a jury trial.