I don't know about some of the specific questions you've asked... but for rude or inappropriate questions, I try to turn it back on them if possible.

E.g. "Eh why you put on weight ah???" "Oh haha you also became so much bigger, aunty!! Same! Eh you want my mum's tips for elderly sagging skin?" (And then sometimes this just defuses things and everyone laughs and it's all good, or they just get embarrassed)

For inappropriate questions or comments, I am sometimes brutally honest, so they are too shocked to respond and learn they shouldn't be asking such things.

E.g. "Eh why you so skinny now ah??? Must beef up!" "Oh I have bulimia. Sometimes I throw up my food. Just did it last night hahaha lolol"

Or (I haven't said this one, but my sister got fed up once and said it) "Why you so long married still no children one???" "Oh I had two miscarriages." crickets

Either deflection or brutal, shame-inducing honesty is often the way to go!