Do you want the coat for autumn or winter?
Coat 1: yes it's quite short for a coat but it covers your bottom (which my dad always told me was important with a coat!) and it's 80% wool so will be quite warm, can button up to the neck, and the hood will help with warmth too.
Coat 2: style over practicality. Yes, the open V-neck will be cold unless you wrap an extremely long thick scarf around your neck and chest.
Coat 3: won't be very warm as the fabric is quite thin. I have a similar coat and only wear it in spring and autumn.