Easter Weekend in major cities

What "other cities" are you referring to?

In Catalonia, "major" cities (namely Barcelona, Tarragona, Girona, etc) don't "shut down"... you can always find somewhere to buy groceries, a restaurant to eat in or a bar to get a drink. The train never stops either, while frequencies will be lowered, public transportation is running all year-round. As per attractions and museums, that'll depend on the particular one, while many will be closed a handful (literally, a handful) of specific days during the year, others are not and they open 363 days (either totally or partially).

It depends a lot on where you're going. In Andalucia museums and other sights may reduce their hours somewhat because of processions passing nearby, and some churches may have more-limited hours since processions start/end there. You'll make slower progress walking through the streets when there's a procession nearby. It is smart to take these conditions into consideration when deciding how many days you will spend in each city.

Enric and Acraven,
Thank you. Ultimately our destination will be Zaragoza. But I thought there might be useful comparisons to Zaragoza in cities of similar size; cities with similarly-sized processions/events; and/or even other places in Aragon if the cultural differences around Semana Santa are that pronounced from region to region. In the absence of information about Zaragoza specifically at least some comparables will help with planning and expectations. Your replies are helpful. Any other thoughts welcome!

Bars never close in Spain, specially if it´s a holiday. Easter is a very popular time to travel for Spaniards and all attractions are open. Most supermarkets and all banks close on Sundays, but bars and restaurants are of course open, it´s a busy day! Mass attendance in Spain is around 11% and religion beliefs are very low, but we do love our traditions and processions on Easter.

Every city celebrates Semana Santa differently, Zaragoza has notable processions but maybe not on the same scale as in Sevilla. Many locals will take advantage of the long holiday weekend to travel domestically so you may find some logistical issues/price increases with hotels in the popular tourist areas, as they will all mostly be open. However Easter Monday, April 10 is a national holiday, so you may find some more shops and restaurants being closed on that day.

I'd say go with the flow and try to keep a flexible schedule. This should help (in English) -
https://www.zaragoza.es/cont/assets/publicaciones/ssantainglesfrances15_accesible.pdf

Easter Monday is a holiday is some autonomous communities (in mine, Basque Country), but not in many others, where it´s a normal day.

MikelBasqueGuide is right, I forgot that Easter Mondays only a public holiday in some regions, like catalunya (where I'm from) and Valencia etc I don't think in Aragon it is though, you may have to double check that.

Thank you all. Very helpful. Carlos, I especially appreciated that PDF. I would not have found that on my own, and it is filled with useful information.

Happy to help, you'll have a wonderful time in Zaragoza, one of the more underrated cities in Spain. I doubt you'll see any other foreign tourist there, it'll be a very local celebration.