1.

She had a short plump figure. Her figure made it difficult to find attractive clothes.
WHICH or THAT

She had a short plump figure WHICH / THAT made it difficult to find attractive clothes.

2.

In spite of this, she had a large wardrobe. I was allowed to help her select something colourful from her wardrobe. She would brighten up the dark day with something colourful.
FROM WHICH and WITH WHICH

In spite of this, she had a large wardrobe, FROM WHICH I was allowed to help her select something colourful WITH WHICH she would brighten up the dark day.

3.

She had two habits. These two habits fascinated me and worried my mother.
WHICH or THAT

She had two habits WHICH / THAT fascinated me and worried my mother.

4.

Hanging from her mouth she kept a lighted cigarette. Her mouth was generously painted bright red or orange. The cigarette was never removed to embrace a child or to talk.
WHICH (twice)

Hanging from her mouth, WHICH was generously painted bright red or orange, she kept a lighted cigarette, WHICH was never removed to embrace a child or to talk.

5.

She was a great talker. Her favourite subject was the lives and loves of friends, relatives and neighbours.
WHOSE

She was a great talker WHOSE favourite subject was the lives and loves of friends, relatives and neighbours.

6.

She recounted scandals to my mother. My mother tried to change the subject if she saw me listening.
WHO