A.  The owner of the property. If the neighborhood is the owner, they are liable and responsible for the maintenance. if the adjacent homeowner is the owner, they are responsible for the maintenance.
The neighborhood contends that they are the sole owner, which would make them responsible for the maintenance.  We know that the indentures state that the Agents cannot erect or dismantle any alley without permission from the adjoining owners.
As per the indentures that they can mow and trim any park or easement.
What other improvements or maintenance agreements they are capable of has yet to be determined.  There may be a stated use for this land in the indentures, e.g. for a only an alley.