The effort expended here is commendable. As you see from the other replies, the general concensus is that these can not be direct impact craters. The paper A RE-EVALUATION OF THE EXTRATERRESTRIAL ORIGIN OF THE CAROLINA BAYS , discusses the topic.

The subject of "carolina bays" and oriented lakes has been much debated. Perhaps you may be interested in yet-another theory - that these are not impact craters, but the splatter of impact EJECTA . You can see my presentation at Perigee: Zero Carolina bay morphology

- Cintos