I see no difference between a trained dog's alert and a statement by a person. Both exist, both express opinions and both can be proved right or wrong by other evidence.
Hmmm. My view is that it's not necessarily that simple.
A dog reacts. A handler interprets.
There is not a single "human cadaver odour" but many components, many of which can occur naturally and can be totally irrelevant, or be present at different stages, or in the presence of some substances, or present in common VOCs between species, but can still trigger a reaction.
Sometimes a whole human cadaver isn't present, therefore the entire spectrum isn't present. A bit of bone probably won't smell the same to a dog as decomposing gut, or a potentially irrelevant nicked bit of flesh in a kitchen mishap. Or blood or semen. Nor even may the dog be able to distinguish between certain "aromas" common across species.
There is also the issue of the fact that the dog may have picked up on a certain amount of "anticipation" in certain areas and Eddie could have been anxious to please by picking out anything within his (undefined) parameters. That's conjecture, but possible,
In the absence of corroborating forensic evidence, the whole thing is just a question mark. IMO.
Is it possible that she did in fact die in that flat? Yes, I don't see how that could be excluded as a possibility. Do the dog alerts prove that? No. Is there forensic evidence to support that she did? No.