3 neighbor's replacement drain fields on MY lot....advice?
As a point of information, a septic tank whose leach field has failed (or whose outlet has collapsed or is otherwise blocked) behaves like a holding tank.
It is not a good idea to plant trees or large shrubs of any kind on a leach field; the roots will get into and clog the leach lines.
The average homeowner who lost his house in the Oklahoma tornadoes should move for good and not rebuild. Too much complexity watchdogging the contractor. Too much a chance to be defrauded.