I agree with previous responses to your question in that more questions should have been asked prior to confirming the sit.
That said even with the best will in the world things will sometimes crop up on a sit that cannot be planned for.
Even if the cat normally isn’t a hunter there is always a first time. The cat may come across an injured bird or rodent and bring it home.
Personally I can deal with live or dead ‘gifts’ but would struggle with a badly injured one.
On a couple of sits we have had bats enter the property - that was fun!