Undergraduate / A challenging experience and what i've learned from it; defining moments for a person [6]

N.B: I am not a professional editor, my advices might be wrong.
You did not give the audiences a really harsh experience. You just told us you faced the harshest ever. However we cannot tell whether it is so harsh or it is just your imagination.

You probably can describe the conflict more specifically. Maybe the fight between your parents or your ideas of the bitterness.
This experience is too common, almost a cleche.

Writing Feedback / (IELTS graph) Proportion of people in household types living in poverty in Australia [2]

You have written too many words(240). You should write less, so you can finish it during the exam period.

Essays / A picnic turned out a disaster [4]

Do you have further instruction or that's it?

You should start with a happier picnic. Then you can give a U-turn.

Undergraduate / 'A Coercive Passage' - Yongzheng Emperor (Common App historical figure) [3]

"No gold is completely pure" in chinese culture "gold" always copper. The pure copper is red. It derectly translation is that "No gold is so pure that looks red, no man is so perfect that never makes a mistake or be misinterpreted"

I think you spent too much time itroducing your ideas.