There are a lot of questions so I will try to answer as many as I know.
Along the southwest shore there is a place called the hatchery. Back in the 1960s, the SCMWR (Marine Wildlife Resources) had constructed a large walled area which is full of stumps and cypress trees as a place to breed striped bass. It was safe from the other fish in the lake. There was a road all around with two concrete bridges. That allowed the water to flow in and out via mess screens. As technology advanced, the hatchery was removed by digging up the gravel perimeter road but left the bridges (they were too well constructed).
Today, if you are brave enough you can fish in there. Once I was in a flat bottomed Bass Tracker boat and slid upon a stump. It took me about 2 hours to rock myself off.
There are a number of fish camps and restaurants. Most are in canals and flats. Catfish is easily the most popular to eat, but all types of food are offered. The place in the picture is in the canal that connects lake Moultrie to lake Marion. If you traveled it's length, it would be about 50 miles.
Fisherman from all over the US come and stay at fish camps as a convenient place to sleep and launch their boats or hire a guide. They are like an old motel complex or trailer park.
The largest catfish caught so far is 109 lbs. 60-70 lbs cats are not uncommon. Years ago, our grandson caught a 44 lb. The lake has striped bass (minimum size to keep must be more than 24 inches). There are also perch and brim (bluegill).
The water levels are around 30-45 feet. About 70 feet deep near the dam.
And yes, there are gators.