12 nights in Spain itinerary advice

It seems like a good itinerary, if a bit rushed. You might consider adding a night to Madrid so you can daytrip to Toledo (35 minutes) and/or Segovia ( 30 minutes) before training to Seville. If you could add a night to Seville, you could daytrip 45 minutes from there to Cordoba by train. There’s a lot of Moorish historical architecture in Cordoba to be seen that could substitute for Granada.
The two nights added to Madrid and Seville would require skipping Granada, if that change works for you.
I would then fly from Seville (SVQ) to Barcelona ( BCN) for your final four nights.
And, yes, I agree that Tangiers does not add much value to this itinerary.

Thanks for your input! I did previously look at day trips to Segovia and Toledo, but am not sure my kids/father will want more towns with churches/history. I mean no offence by this - my H and I would love this - it's just the reality of teenagers!

Looks fine. Just a suggestion - if Santiago Bernabéu Stadium in Madrid is a focus, then when in Barcelona you might want to tour Camp Nou (although I'm not sure when it reopens, so Estadi Olímpic might be the option).
Also, if your family get a bit bored with Seville history/churches, I'd go to Setas and walk across that or spend an afternoon in Almeda de Hercules. Both are interestingly different from the guide book "must see because it is old" stuff.

Looks like a great trip! Just a couple of comments:

Popping into Reina Sofia to see Guernica might be more fun than the Prado (bocadillo calamares across the square at El Brillante are delicious!).

The aqueduct and alcazar in Segovia are awesome regardless of age and walking the walls in Avila is fun too.

Cordoba is a more relaxed, inviting city than Granada, and the Mezquita is incredible .

The fun In Montserrat is getting there and the scenery. Not sure teens would be interested otherwise.

The Dali Theatre-Museum in Figueres is an alternative daytrip from Barcelona.

Have fun!!

Thank you for the input! I've decided to remove Granada and base more out of Sevilla. Revised:
1 arrive Madrid early AM / easy day
2 Madrid
3 Day trip to Segovia or Toledo
4 Train to Sevilla
5 Sevilla
6 Day trip to Cordoba
7 Sevilla
8 Fly to Barcelona
9 Barcelona (Parc Guell / Sagrada Familia)
10 Barcelona
11 Day trip to Montserrat
12 Barcelona (Montjuic / Olympic Park)
13 Fly home from Barcelona

My only hmmm now is, do I add another day to Madrid and remove from Sevilla or Barcelona? Was thinking that by basing out of 3 cities only, we have a bit of wiggle room for day trips - and can even split up and do different things based on our interests (eg. if the kids want a chill day or two).