Can you check these sentences,please? Thank you very much.

1) How big/large is the population of New York? Are they both correct?
2)He was dismissed last year and he hasn't found a job yet.
3) He's been working for three years as a mechanic at an assembly line.
4) The girl in the picture is sketching new designs. In the background there is a manikin (or a bust). A design (the drawing of an item of clothing?) hangs on the wall next to a palette (a sort of calendar showing the different colours?)
5) A crowd of photographers and journalists are standing on the right. They are taking pictures on the models on the stage (catwalk?).
6)New designs are shown on the catwalk. Two models are walking down the catwalk. (?)
7) What is your favourite outfit? Would you like to work in the fashion industry? What sort of clothes do you like wearing? How often do you buy them?

1-"large" is better.

2-needs a comma. Where?

3-...on an assembly line.

4-mannequin, design, palette

5-stage is fine.

6-repetitive. Try this: New designs are being shown. Two models are walking down the catwalk.

7-OK