What kind of bushes can handle being landed in the dry and live in the water 7 months out of the year. I need to add structure but can do brush piles due to branches moving and stopping the drain up.

Bald cypress trees should thrive in that environment in Arkansas. Their "knees" would add some structure to your lake bottom.

There are also various types of willows that should do well in that situation, but some of them spread like crazy, and might NOT be a good choice for a shared lake.

Willows are lovely, but tend to be water hogs.

I don't know of any "bushes" that can survive being completely flooded for that amount of time and still be alive when the water recedes.

I’m going to use a bunch of cedars.

Yeah the willows around here get out of hand around the lakes fairly quick