Just to comment on the baggage thru-check:

My experience is that once a connection hits 6 hours (even if international) when departing from the US, DL systems tend to default to short-checking. This also correlates to the time when the app starts to jumble a trip up into a "multi-city" even if the full website still shows it as a roundtrip or one-way as appropriate. A good agent can definitely override and thru-check your bag, but you might have to push for a supervisor. I usually make sure in cases like this I start my convo with the agent as "Hello. My final is XXX." That seems to get them going in the right direction to make sure the tag says XXX. If it defaults to short-checking to a connection point and prints as such, the agents are usually quick to start the whole "you'll have to claim and recheck" speech without making an attempt redo the tag and that's where the push for a supervisor comes in.

Note if departing a non-US station bound for the US and you have this issue, greater than 6 hours, the system views it correctly as just a long international transfer and defaults to thru-checking. It's just departing from the US I seem to have this issue on occasion.

Now the caveat here is that you will obviously be overnighting in JFK, so YMMV with the agent, however pointing out you don't plan to leave the secure area could work in your favor with the minute suite reservation.

Funny you mentioned this as I'm looking at a possible international trip this fall with a 6 hr 58 min outbound connection and my mind went through all this earlier today.

Edited to add: booked the above mentioned 6 hr 58 min connection tonight and both the app and full website show a multi city now. I’m anticipating a default short check situation will occur. Hopefully when the time comes it’ll be a knowledgeable bag drop agent.