Pat, this sounds like a great project! Here are a couple of thoughts. First, take lots of pictures of the parts of the lake that don't have water. You'll forget exactly where things are otherwise. Also, you can draw a map of the depts and contours of your lake easily at this stage.
Next, you can make bottom structure at this stage easily. I personally like ridge and channel type of cover. We also have a shallow flat surrounded by deep water. When you break these small dams open to connect them to the main lake, rather than one cut in the middle, you might make a cut at each end leaving an island or underwater ridge.
If you open the small dams at the ends, you might be able to wait before you have to connect the small lake to the main lake. That will give your fish time to get bigger and thus have a better chance of survival.
Are there any other species such as red-ear sunfish in your lake?
From my perspective, having a lake fill slowly like yours is a great advantage. We started our lake in 2000 and just finished it this year. Along this time, I was able to incorporate many ideas from this forum into the new parts of the lake.
