No one is checked in on the return flight yet which is why no one is on the list yet.

As for CO choosing to hold all 8 seats for sale, that is their prerogative, particularly if they think that they can sell the seats or that they'll need them for handling misconnects. I would be surprised if they were choosing to do it wholesale across the plane type, but they could still do it.

Also, the fact that it took intervention to get you on the list the first time might mean that there is something wrong with your reservation causing it to get passed over, but that seems unlikely since the chances that there are NO elites on the flight other than you are pretty low, so it would appear that they are holding back the inventory.