Sunday, 11pm onwards to 2am in the morning of Monday.
I'm ok with walking 15 minutes to Chinatown, but is it safe?
Also I assume the subway doesn't run during that time right? So the only other choice is uber/taxi?
Actually from SotP you could also get to the Cross via William Street. There's late night there as well, so things like Thirsty Bird, a few pizza joints and stuff. There's also Huberts which is open late and that is up on Bligh Street.
Although restaurant wise you will be struggling for something nice, even places like Palings close at midnight, and when they say midnight they mean midnight.
Even in Chinatown past midnight/10 pm your going to be limited in choice to mainly Golden Century and a few places on Dixon Street. On the train, it runs but still doesn't get you that close to Chinatown. This ain't New York.