Will life survive? Yes. Because “life, err, finds a way”.

Well, then we haven’t made it inhospitable.

Anyway, I’m not sure why the aliens would be interested in a planet with a slowly dying mega fauna. As I understand OPs question they want to literally destory the entire thing or at least want it properly sterilised. Humans won’t be of any help with either of those, so waiting for humans to do something wouldn’t really help the aliens.