bonefish,
Have you ever introduced yourself to the conservationist at your county NRCS office?
It might be a good idea. They should know what grows best in the county for pond edges and erosion control.
There is even a chance they could have some grass seed leftover from their 2022 programs that they could give you, or sell you at a reduced rate!
Always worth a shot, and that is usually a good person to know anyway for future questions or problems.