Your questions make me confusing, though I will try to answer them.
"If I should become..., what is it like?"
If I should become nice,
내가 (만약) 멋있어진다면,
If I should be like her,
내가 (만약)그 여자처럼 된다면,(You already look nice, Melike.)
How is it?
How is it to be a swimmer?/What is it like to be a swimmer?
수영 선수가 된다는 것은 어떤 걸까?
How is it to have a home?/What is it like to have a home?
가정(집)을 갖는다는 것은 어떤 걸까?(가정=a family, 집=a house)
What are the things you like and you hate?
네가 좋아하는 것은 뭐야? 그리고 또 싫어하는 것은?