Unless that potential US destination has onward connectivity with JetBlue I would discount it.....?? Or indeed American, giving the alliance on the North Atlantic with IAG..
The feed will be Dublin (40-50 routes) on this one, and this will be the route unless there is a sudden change between now and the announcement.
I have heard some whispers that there could be another little surprise in store at the announcement but can't verify it so won't speculate but it relates to the US.