I do know that Crescent 19/20 tends to have an extra coach on weekends during the summer and when big things are going on in NOLA. It departs NYP on Thursday evening.
Not gonna happen unless somebody comes up with the money. The station they use was built as a suburban station when it was almost in the country. There has been talk of a replacement station 5 or 6 miles north, but again, where is the money?
Can't think of anything much more convenient than 2 blocks away. The nearest MARTA station with long term parking is either Lindbergh or Brookhaven, both about 3 or 4 miles away.
Most recent info I have seen is that Corp of Engineers is shooting to close the spillway in about 2 weeks. After track inspections, the City could be running all the way again.
I was on 20 numerous times over the past several years as a Trails and Rails volunteer and breakfast on 20 was never served until about Slidell, sometimes a little later.
You can get dinner on #19 into NOL, although it will likely be the Express menu with about half the choices. #20 does serve breakfast out of NOL, usually beginning around Slidell, about an hour out.