I'm going to check again for the same flights next week to see if any other class availability opens up but if anyone could shed some light on why there could be zero availability in the lower classes but the seat map shows a wide open flight I'd apprecate it. Thanks and safe travels!
As has been discussed on this forum numerous times, the seat map is a very poor indicator of how many seats have actually been sold. There are numerous ways that you might buy a ticket but not have a seat assigned. Trust ExpertFlyer much more than the DL.com seatmap.