I actually did this same trip 3 weeks ago (well not exactly, BCN-RAK then RAK-MAD on IB). Fantastic TR, you clearly have a gift for photography as well as prose.
One slight correction to make regarding lounge access at BCN:
The BCN lounges are operated by AENA (the airport operator) and are more or less shared by all the companies. After you pass through security at T1 (all gates go through the same security) you can access the big lounges in the main departure area. There are 2, one which is basically the de-facto *A lounge and another that admits OW and ST pax, as well as PP cardholders and some other programs.
To enter the D (or E) departures area, you must go through passport control and may not return to the main terminal. These areas are for non-Schengen departures, including the BA flights to LHR and VY flights to RAK. There is a very nice lounge in this area, immediately to the left after the passport check.
I accessed this lounge a few months ago without incident as an AA EXP traveling BA. Most recently I got in by handing the dragon my EXP card and BP (it was printed on IB stock). She looked confused and typed for a while but eventually let me in even though my flight was neither operated nor marketed by a OW carrier
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