Then why would they list HNL-ATL, but not HNL to other cities?

I hope you're right, but I don't think Delta rolled out much info to their employees prior to launching domestic EC. I would tend to trust the published data and info posted on FT (including by SMI and other Delta reps) much more than what a phone agent tells you at this point.

You yourself pointed out that the DL agent's statement contradicts every available bit of information about domestic EC. I would consider the agent a secondary source to the consensus available everywhere else.

Based on all reports, the only way this route will have extra recline is if the plane is an international configuration equipped with EC, which typically does not serve this particular route (i.e. IROP or repositioning).