Does a CVT extend engine life?
 

I'm not too sure about this but do you think a CVT vs. a manual or a regular auto extends the life of the engine by keeping rpms "smooth" or constant (more or less)?

I get what you mean, but the difference would be minimal. It would just allow the sensors more time to catch up with the engine. If there were a difference in anything, I'd say it would be good for your axles/hubs.