You can check out Gringo Post gringopost.com – they have a daily newsletter that goes out via email. You will see many groups like you are describing that welcome people to participate. There are LOTS of fun things to do in Cuenca – your heads will be spinning and I’ll bet you won’t be able to do all of them!
One of the acting groups is: Azuay Community Theater A.C.T. Ninfa Gonzalez: ngtrade5@hotmail.com They are currently working on a production for sometime in April. Also, there are several choirs in town. One wonderful group is the Cuenca International Chorale. contact: Phil Kennemer kennemer.phi1@gmail.com Another fun group is the Cuenca Dance Mob. For more info, contact: David Naccari danceclubcuenca@gmail.com
Have fund and good luck!