Sevilla or Cordoba to Madrid Airport for 1:15 pm flight

3) Do I play it safe and overnight either 1 or 2 nights in Madrid to end the trip, even though my flight out on the last day isn't until 1:15 pm?

I’d recommend spending the night prior to your flight in Madrid, just to be safe.
You don’t want to risk missing your flight due to a train strike or whatever.

In terms of your itinerary,
I’d suggest you consider changing your route to something like this:
Travel to Córdoba on day of arrival (2N) >> Granada (2N ) >> Ronda (1-2N) >> Sevilla (4-5N) Madrid (1N) >> Fly Home

If you choose to skip Ronda, add an extra night to Córdoba or spend at least an overnight in Toledo.

Wishing you a wonderful trip!

Edited to add…
Keep this in mind too.

If your flight out of Madrid is an international flight, the general recommendation is to arrive 3 hours prior to your flight.

Too risky for me. I vote for staying near, Madrid’s airport or in Madrid itself.

Nope way too risky. You should stay in Madrid the night before the flight preferably at a hotel near the airport although you could stay in the center city as long as you head for the airport by about 9 am.
I would do this: arrive in Madrid and take the train to Granada staying two nights in Granada, one night in Ronda, four nights in Sevilla, two nights in Cordoba, and one night in Madrid. If you’re not interested in doing a lot in Madrid arrive by train late afternoon eat a nice dinner near your central city hotel do the paseo and leave for the airport by 9 am. On departure day. You’ll have a much nicer ending to your trip.
You could also sequence it Cordoba, Granada, Ronda, Sevilla, Madrid.

Thanks @priscilla @jaimeelsabio @buffalo ,

I have altered my plans to blend all of your wise and useful advice. Much appreciated! Here's the new itinerary.

Arrive MAD early (5:50 a.m.) on Saturday. Train to Cordoba (many options arrive before noon)

Cordoba - 1 night (I have more than half a day on day of arrival and next day before moving on.)

Sevilla - 3 nights

Ronda - 2 nights

Half day in Malaga to see Picasso Museum on my way to Granada (good bus connections through Malaga)

Granada - 3 nights (need to be in Granada on weekend to make winter schedule night visit to Alhambra)

Madrid - 1 night - ahead of my flight the next day (arrive early enough to visit Prado and maybe Royal Palace)

Cercanias to Airport on morning of last day - risk and angst removed.

Looks good to me. It’s a matter of opinion about 2 nights in Ronda and 3 in Seville - I might be looking at 1 in Ronda and 4 in Seville, but there’s no wrong answer. I like that you have given Granada 3 nights - I really like Granada and there’s a lot besides the Alhambra to see. Wise choice on last night in Madrid.

If it were me, unless you want to walk the nearby El Caminito del Rey (which is awesome!), I would skip Ronda. Instead, you could spend a night or two in Malaga and/or add a day to Madrid and take a daytrip to Segovia.

Have a great trip!

Your revised itinerary looks better.
Keep in mind that there’s more to see in Sevilla so you may want to consider adding a night there by taking one away from Granada or Ronda.
Having said this, this is your trip so you decide what’s best for you! Enjoy beautiful Spain!

Just want to say these have all been thoughtful, helpful replies. Thanks everyone! I’ve got some time, so I’m letting the options percolate - with a commitment to giving Sevilla and Granada each their due. At least the last night in Madrid question is settled.