1. no one could possibly have survived
That's not the same thing as the actual identification of bodies. We're all aware of horrendous accidents that no one could possibly have survived -- except that somebody does walk away unscathed.
In this case, the statement that "no one could possibly have survived" seems inconsistent with the retrieval of Saddam "with a gas mask over his face." That doesn't mean that he did survive, of course, but his body was apparently intact, so it does appear that somebody could, in fact, possibly have survived.
2. How would you square this with the mention of the timing of the bombing in Saddam's speech?
Obviously prerecorded or its not Saddam. Either way, the CIA probably wont 100 % confirm it just yet. At least not until we have a complete and unconditional surrender of all Iraqi troops and our M1 tanks are finally rolling into Baghdad.