Originally Posted by
headinclouds
Lastly, can one lounge hop the arrival lounges, or is one restricted to the arrival lounge of the operating carrier?
No lounge hopping because unless you are connecting, there is only one arrivals lounge you would be eligible to use on both occasions as GCH: If you take the BA flight, you are only able to use T5 arrivals, and if you use the AA flight, you'll only be able to use the AA arrivals lounge in T3.