JFK lounge

Hi All. Long time no post!
I'm off to JFK in March in UC - on the return leg I'll book the last flight out just to be safe sure of making the flight. Likelihood is I will be at the airport around 7pm - is checkin and lounge like LHR where you can checkin and access the lounge before the "usual" 3 hours?
Also, can I take a guest into the JFK lounge?
Thanks.
I'm off to JFK in March in UC - on the return leg I'll book the last flight out just to be safe sure of making the flight. Likelihood is I will be at the airport around 7pm - is checkin and lounge like LHR where you can checkin and access the lounge before the "usual" 3 hours?
Also, can I take a guest into the JFK lounge?
Thanks.