I can't answer all you questions. I talked to the LA D O T D this AM and the Rigolets HWY 90 bridge is down again. They have had it up and keep getting into electrical problems. They have removed and rewound the motors, but are having other electrical problems off and on. The CSX railroad bridge in the Rigolets has a span sunk.
The Chef pass bridge is open to marine traffic, but you will need high tide and a knowledge of the lake.
I hope we get a response from someone who has been in MS sound recently.