By the end of 2014, Pawnee Commons is completed. It is revealed that in January 2015, a new apartment complex, called Morningstar, began construction on the block next to Pawnee Commons. Consequently, Ann's old house was demolished.

Does Leslie get her park built?

Leslie did get to build the park in Lot 48, but in season 7 she fought for another park, although a much bigger one. ... In the end, she got the land and gave Pawnee its National Park. By the end of Parks and Recreation, Leslie had given Pawnee two parks.

Did they ever fill the pit?

In the Season 2 episode of Parks and Recreation titled “Kaboom”, the Pit gets filled in, thanks to the efforts of Leslie, Andy, and Ann, and that filled-in lot is then also featured in numerous subsequent episodes.