We are preparing for a trip to BCN using DL miles in June. Unfortunately I could only book seats from PDX to MAD(but we did get biz class). So we are left to buy our own tickets onward to Barcelona. We arrive around 8:30 in the morning. So I was hoping to make a reservation for a connecting flight at around 11:30 am. Here are my questions:

What is a legal and recomended connecting time international to domestic in Madrid?

What happens if DL is late to Madrid from Atlanta? Would we be left to buy a new connecting ticket? Are the European carriers tight about this or would we be able to just grab the next flight if we miss ours?

What airlines does anyone recomend...Travelocity offers 58$ oneway fares on Spanair, more money for Air Europa and spendy 119$ oneways on Iberia.

Lastly, do all the domestic planes leave from the same terminal as Madrid international? If not how much transit time between terminals. Do all domestic flights leave from the same airport? is it the same as intl?

Thank you so much FTers especially the Sitges crowd your posts have been quite helpful. By the way we fly home from Italy so this is only a one way deal.