I'm not holding my breath given the way things have gone so far.
For this entire thing the lack of cooperation on the part of CSX makes no sense. This is a near flat and straight piece of railroad with CTC and not that high a number of freight trains. Due to lack of grades you are not going to deal with freights grinding up hill at 10 mph, although given the tendency to minimize power to just above stalling it could take the freights 5+ miles to get up to speed. They should be regarding anything they get out of Amtrak as a bonus because so far as the ability of the current facility to handle a couple or more passenger trains each way should require next to nothing in improvements on their part.
Extension of grade crossing circuits may be an issue, as the line does have a gazillion road crossings once out of the Louisiana swamps as the area across Mississippi is essentially an urbanized strip. But that should be in place from the days of the extended Sunset Ltd. This is after all the "Redneck Riviera".
Another thought, for the length of line once a day service makes no sense. It should be 3 to 4 a day spread out, morning, mid day, afternoon, and evening, with the last two listed being one if you want only 3 trains per day. If I recall correctly, when North Carolina went to a third train they carried more per train than they did with two a day.