As a follow up, is there a lounge available if traveling on a 125 ticket, but traveling on Iberia, well Air Nostrum in the J Cabin?

whilst I’m “here”, is it possible to reserve seats on IB/Air Nostrum on a 125 ticket? In MMB, when I click select seats for that flight, I get a message to state that we can’t do that right now and to wait 48hrs after booking. I’m well past 48hrs. If I use the BA PNR on the Iberia site, it finds the itinerary, but informs me that another company controls the ticket and no seat map is displayed.