Not unless it is AA's fault. Weather or air traffic control delays won't be AA's responsibility.

Is he sure he doesn't want to fly the Virgin non-stop LGW-LAS?

You can re-check your bags before you exit through the sliding doors after clearing immigration and customs. Then you need to go back upstairs and re-clear security.

Sorry I forgot to follow up on this.

The reason I flew AUS-JFK-GIG was that there was a fare deal that required me to be on the JFK-GIG flight. On the return I flew GIG-MIA-DFW-AUS. At least when I made the trip, there weren't any nonstop flights between DFW and GIG. I think there are only 2 MIA-AUS nonstop flights daily, and neither worked well for me.

I checked in for my whole trip in Austin (AUS-JFK-GIG); checked a bag all the way through, and received both boarding passes. My AUS-JFK got in early, so I had over 8 hours. I stopped in the club (I had heard a rumor that they may let me leave my bags there, but not true) briefly, then headed down to baggage claim. I left my bag at the left luggage desk, then took an Uber to Brighton Beach, met a friend to swim. The water was freezing (I asked her not to tell me until we finished, she then told me it was 61F). After that, I walked down to Coney Island, ate at Nathan's (the main one on Surf, across from the subway station), then took an Uber back to JFK.

I'd guess I was back at JFK around 7pm. Had plenty of time to retrieve my bag, clear security (TSA Pre), visit the lounge (with a shower), have some snacks and relax, then head to my gate.
As someone else mentioned, things were pretty quiet in T8 by that time and most people in the lounge were on my flight to Rio.

If arriving at around 23:00 on a BA inbound and then leaving on an AA domestic at 06:00, can the bags be dropped off immediately or would you have to wait until AA check in opened in the morning?

AA does not open check in until 0300.

But if travelling on one PNR/Ticket LHR-JFK-LAX, can the bag be dropped off using the 'connecting passengers' route or would I have to collect my bag, exit landside, and make my way to T8 with my bag and wait until 03:00? Is the bag drop point in the connections area open 24 hours?

Now, going for a swim and visiting the original Nathan's famous was well worth the out of the direct line to GIG thru JFK trip !! I had not thought of that as a summer layover time killer (Coney Island) but that's a good one to remember.

AA sells a ticket TXL - JFK - MIA with 1:25 min Connection Time in JFK. The MCT is 1:45 min.

Arrival and departure should be in T8. I have not Global Entry and i am European.

How do you see my chances to get the connecting flight ? How Long are the actual waiting times at Immigration Kiosks ?
Delay of the incoming flight often 5 - 15 Minutes. I have a preferred seat .

Thanks @all :-)=

Without GE, there's no way I'd risk 1:25. Picking a random date in Oct, I even saw TXL-JFK-MIA offered with an 1:15 connection time; that seems insane.

If the MCT is 1:45 -- I'm having trouble finding that posted anywhere -- you should be able to call AA and change without a change fee. You didn't specify dates, but on the Oct date I selected options through JFK were quite limited; you'd do better routing through LHR.

Thanks @SpammersAreScum :-)

That Connection gives me better seats (XL-Seats by AB without costs and 767 with 2 seats in the row...)

Thats why i would like to choose that (not yet booked).

what�s the risk ? AA should rebook us, if we don�t reach the MIA-Flight.
Our Ship in MIA starts next day afternoon...

Or i miss another fact ?

If your connection is indeed under MCT it is likely to be automatically cancelled by AA. The later this happens the fewer alternatives remain for you.

Thanks. Good to know. Do they only cancel before or do they rebook ?

But i see also, that the connecting flight very often delayed in the past..up to 2 hours..

and even i have seen this on EF:

Minimum Connect Times
Share Results

STANDARD.D/D...D/I...I/D...I/I.
ONLINE 1.00 1.15 1.45 2.00
OFFLINE 1.00 1.15 1.45 2.00
** OR * ARE ALL
AB-AA ID 1.15
**-AA ID 2.00 TRM 7 - 8
AB-** ID 2.00

You will automatically be rebooked but the connection they give you may not be to your liking or even make much sense. Moreover they may or may not notify you when this happens (I've seen both).

Regarding MCT, your information appears to contradict itself: two rows below it says AB-** ID 2.00. No idea what is the correct answer, a call to AA may resolve this, however if you mention your particular reservation they may deal with it on the spot.

Does the ** mean connections to all except AA?

seems to be..

AB-AA ID 1.15 (Connection AB International -> AA domestic)
**-AA ID 2.00 TRM 7 - 8 (Connection other Airlines incoming T7 to domestic AA in T8)
AB-** ID 2.00 ((Connection AB International to all other exept AA)

btw, i have booked the flight now. I have seen, that the connecting flight AA 235 is very often delayed, sometimes more than 1 hour).

Otherwise i spend the night in NYC and fly next day to MIA. Cruise starts at 7 pm..