Added 7 minutes later
And here are a couple more nuances, just in case something is still unclear.
No Night Kill can be used on oneself. Goodblade Timmy and Jose are displayed as humans. If Timmy is checked, it is reported that he has been cured of the infection. The role of Scotty is revealed only upon a kill, not upon an execution. It's the opposite for Maria. In case of an unsuccessful kill, the reasons for the failure are not revealed to the killers.