Please don't think you were cruel to Oliver because you yelled at him and squirted him with water. I've bout drowned Chester several times when he scratches the door. If I didn't yell at them once in a while, they'd think I was sick. It's not cruel, it's human. They know very well what they ought not do but like to test us by doing it anyway. That's called being a cat. You did your best with Oliver. Maybe his new owner wasn't it a position to get him yet and his stay with you was like a stay in a hotel until his new owner could get him. There are no coincidences you know.