Randi,
Some people have a fundamental objection to cremation.
The chamber that was used was like a baro chamber used for decompressing divers with the bends. It was completely air tight.
The Kryptonite in this case was a hybrid form of red/green and resulted in a complete transfer of the physiological characteristics from Clark to Lois. Dr. Klein was unaware of who he was dealing with. That is why when they went to see him, after his analysis he stated that Superman was now physiologically fully Earth human whereas Superwoman remained FULLY KRYPTONIAN human. It wasn’t until they revealed their true identities that he realized that something serious was up. Until that point he had believed that they were both Kryptonian.
As far as it happening again, that effect affected both of them simultaneously and will not repeat. They tried and failed so the change is irreversible.
There is just as much chance of Clark being reanimated as there is of that happening to Alt-Lois.
