Rainman, this post is a nice slow softball lob, hanging over the plate and just ready for you to swing....

gklop, welcome to the forum! Rainman is one of our local experts on tilapia and will help as will others I'm sure.
I'm from W Mi and tilapia will not overwinter in my pond so I'm sure some of them may die and settle, or be picked off by predators or turtles. I can't say if this is a good thing or a bad thing though...
What part of Ohio are you in? I'm assuming water temps get below 50.
What strain of tilapia where you looking to stock and my last question is, the customer that didn't 'harvest' in time, how were they thinking of harvesting them?