My family and I are booked on JFK-MAD-SVQ on two separate tickets. Both are on IB. The connection time is 6 hours at MAD. I have two questions.

For my family who do not have checkin luggages, can they get a boarding pass for SVQ at a transit desk at Terminal 4S?

I have checked in luggages, do I need to get the luggages and exit Terminal 4S, take the train and re-check in at Terminal 4? Can I check in the luggages at the transit desk instead?

Since we have a long layover, can we use the Plaza Mayor at Terminal 4? We all have Priority Pass.

Thank you!