I would like to comment on your second point.

2) Don't treat Singaporean passengers like 2nd class citizens compared to Ang Mohs

Why is this so? As a Singaporean myself I said that too but after working with @#%^&%, i know what's the reason behind this.
"Ang Mohs" are more polite and well maybe they greet and reply you back well maybe not all but majority compared to singaporeans.
Like in this situation: When they are boarding, we would greet them "Good Morning,Sir/Maam..Can I have your passport and boarding pass?" their reply would be "Hie,GOOD MORNING,how are you doing? Certainly,here you go with their passport.
Their greeting is much more satisfied,you feel happy greeting them. Its courtesy,manners!!
Even though they are traveling in first/business class,they greet you back with a smile and after checking them in they sometimes would say "have a good day". It makes us happy too working after long hours! we are not slaves working.

In another situation,like the singaporeans they just can't be bothered. when we greet them, they just kept quiet and hand the passport. I am saddened by this as a singaporean myself and after that I myself know that everyone always says that they get 2nd class service, i would greet them by their surname,"thank you mr.**"
They would simply snatched back the passport,boarding pass and have arrogant look like(i am traveling on a 5star airline) and walk away looking behind at the boarding area waiting to rush in to board the plane.

Everyday as a only 20year old girl working as a attachment from school, I would think life is tough. Why are Singaporeans like this. "Kiasu". And when they don't get their seat that they want, we would apologise to them and tell the reason why. they would snatch their boarding pass and stare at me and walk away. yes it was like that. only i can say 1/4 of singaporeans are nice. the bad ones sometimes are big people from some big company("big shots" which i check) so they look down on us working. LIKE THAT?!