Not sure if there's the footprint for it either.
I would think far more likely is a renovation of the JFK AC, which is due for one, with maybe an expansion (if possible) and a joint AA/AS deal, like what AA did when BA moved in. At minimum if they can put the checkin desks at the entry/gate level (like AA already does at LAX T4 and ORD), the big lobby area can be reclaimed for lounge space. It appears from the HA website JFK T8 map that AS will always be flying out of the far concourse where the AC is located, so it makes sense to have a lounge in that concourse.

For JFK AC users, there is often a less occupied room immediately opposite of the check-in desks, by the stairs. It's easy to miss.