On jumps, no. On flats, yes. People tend to get stuck in a 180 rotation if they focus to hard on a 180 off jumps. The awareness in the air for a 180 and 360 are different and so are the feelings. Also once a 180 is mastered, it becomes the more comfortable of the 2 if you start with a 180. You will tend to forget to keep your head looking over your shoulder or you will get scared and not continue to look over your shoulder to complete the 3.

Yes

Yes it will help u start the rotstion

Yes

Ofcourse!!

Yes

Yes, 180 will help you

Yes