You do need to go to the domestic terminal I can't answer the specifics of J to Y access on a separate PNR but the Slow lounge definitely accessible with Silver / Gold status unless something has changed. FYI I was there a couple of weeks ago and unless they moved the project along faster than expected, you should be aware there are currently no showers / restrooms as they're under renovation (which is annoying after an overnight flight). And it was busy, busy, busy!
Last edited by Fritz; Dec 7, 2017 at 12:44 pm
Reason: spelling