EC-MCS is an Airbus A320 version 200 which Iberia got as new in August 2014. It carries the name Playa De Los Lances. It is a leased machine.
Picture from Helsinki Vantaa airport 3.4.2018 by Ilkka Siissalo.

Iberia Express is a Spanish low-cost airline owned by Iberia, which operates short- and medium-haul routes from its parent airline's hub at Adolfo Suárez Madrid–Barajas Airport, providing feeder flights onto Iberia's long-haul network.

EC-JEJ is an Airbus A321 version 200 which Iberia got as new in 2005. It was transferred to Iberia Express in February 2016.
Picture from Trondheim Værnes airport 8.6.2019 by Ilkka Siissalo.

Another picture of the same EC-JEJ.
Picture from Trondheim Værnes airport 8.6.2019 by Ilkka Siissalo.

EC-LUC is an Airbus A320 of Iberia Express. It is from the year 1999.
Picture from Málaga airport 11.11.2019 by Ilkka Siissalo.

Iberia Regional is a marketing name used by Air Nostrum, a rather small airline which operates in close cooperation with Iberia.

Sorry for the poor picture quality, but this is a rare plane to see. This is a Bombardier CRJ-1000 owned by Air Nostrum flying on behalf of Iberia. CRJ-1000 aircraft are rare as Bombardier backed out of aircraft business, sold its newest aircraft to Airbus and discontinued this CRJ product family. As an end result there are less than 30 flying CRJ-1000 aircraft today. This one is owned by Air Nostrum, flying on behalf of Iberia as Iberia Regional.
Picture from Frankfurt am Main airport 3.6.2033 by Ilkka Siissalo.

Again sorry for poor picture quality. This is Air Nostrum's ATR-72 branded as Iberia Regional and with large "Visit Andorra" stickers. This machine is taking care of most of the traffic between Madrd Barajas and Andorra La Seu d'Urgell airports. Technically La Seu d'Urgell is not in Andorra, but very close to it. Andorra is such a mountaneous piece of land that there's no way to build an airport there. But Andorra does have several heliports.
Picture from Madrid Barajas 12.6.2023 by Ilkka Siissalo.