I just bought a home made of all cinder block. The previous owners covered the exterior of the house with Polyiso Rigid Foam Insulation Board and then cedar siding on top of that which i would like to remove and replace with stucco. Should i keep the insulation on the exterior of the house and stucco over it or should I remove the foam and stucco directly over the block?

In addition, I found a stack of about 20 – 2″sheets of the Polyiso foam board in my attic. Can i use these to insulate my basement or should I be using a XPS foam board?

Thanks for your help.