If I play a {killing wave} let's just say for 5. My opponent responds with a {cloudshift} on one of his creatures. Does that creature still live?
No his resolves first at least that's how I think it works
Yeah when {Cloudshift} resolves killing wave is still on the stack. It doesnt check for creatures until it resolves.
Board wipes don't target, so cloudshifting won't save them the same way cloudshift saves a creature from {murder} effects (by making the shifted creature into a new target)